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一种用于相变存储器的Sb-SiN薄膜材料及其制备方法 【EN】Sb-Si for phase change memoryNThin film material and preparation method thereof

申请(专利)号:CN202110032271.5国省代码:浙江 33
申请(专利权)人:【中文】宁波大学【EN】Ningbo University
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摘要:
【中文】本发明公开了一种用于相变存储器的Sb‑Si3N4薄膜材料及其制备方法,特点是其化学结构是为Sbx(Si3N4)100‑x,其中15≤x≤50;其制备方法步骤如下:采用高纯度圆块Si3N4和Sb作为靶材,通过磁控溅射装置,采用双靶共同溅射方法,通入高纯度氩气作为工作气体,以硅片或者石英片作为衬底材料,对其进行表面沉积;调整Sb直流溅射功率为10~20W,调整Si3N4靶的射频功率为30~60W,在室温下,溅射30min得到Sb‑Si3N4薄膜材料,优点是具有较高的结晶温度和较强的十年数据保持力,较快结晶速度,较好的热稳定性,以及较大的非晶和晶态电阻率。 【EN】The invention discloses Sb-Si for a phase change memory3N4The film material and its preparation process features that it has chemical structure of Sbx(Si3N4)100‑xWherein x is more than or equal to 15 and less than or equal to 50; the preparation method comprises the following steps: using high-purity round Si3N4And Sb as a target material, introducing high-purity argon as a working gas by adopting a double-target co-sputtering method through a magnetron sputtering device, and performing surface deposition on the substrate material by using a silicon wafer or a quartz wafer as a substrate material; adjusting Sb DC sputtering power to 10-20W, and adjusting Si3N4The radio frequency power of the target is 30-60W, and the Sb-Si is obtained by sputtering for 30min at room temperature3N4The film material has the advantages of higher crystallization temperature, stronger ten-year data retention, higher crystallization speed, better thermal stability and larger amorphous and crystalline resistivity.

主权项:
【中文】1.一种用于相变存储器的Sb-SiN薄膜材料,其特征在于其化学结构式为Sb(SiN),其中Sb的原子数百分含量为15≤x≤50。 【EN】1. Sb-Si for phase change memoryNThe film material is characterized in that the chemical structural formula of the film material is Sb(SiN)Wherein the atomic number percentage of Sb is more than or equal to 15 and less than or equal to 50.


说明书

【中文】

一种用于相变存储器的Sb-Si3N4薄膜材料及其制备方法

技术领域

本发明涉及相变存储器材料领域,尤其涉及一种用于相变存储器的Sb-Si3N4薄膜材料及其制备方法。

背景技术

现如今,电子产品的广泛应用促使着存储器不断发展,相比于目前非易失存储器市场的闪存存储器,相变存储器(PCM)不仅解决了循环次数较低(~106)和写入时间较长(>10us)的问题,还在大容量、高密度、高速、低功耗、低成本等方面显示出明显的优势,PCM存储单元被证实在5nm技术节点之前不存在任何物理限制。此外,其造价低,制作工艺简单,存储密度高,功耗低,数据保存能力强等诸多优点使相变存储器备受瞩目,被认为是最具有前景的非易失性存储器之一。由于相变存储器可以在电或光刺激下在亚纳秒范围内快速且可逆地在晶态和非晶态之间切换,具有极佳的非易失性,出色的耐久性以及两种状态之间的高对比度性质,使它在军用和民事方面广泛使用,在航空航天等领域具有极高的研究价值。相变存储器的原理是利用电脉冲(热量)使存储介质材料在晶态(低电阻)与非晶态(高电阻)之间相互转换实现信息的写入与擦除,信息的读出由测量电阻的变化来实现, 期间不可避免的产生焦耳热,因此,相变材料的热稳定性对于相变存储器的研究与发展非常重要。

在相变材料中,锑(Sb)具有较低的熔点和较高的结晶速率引起了越来越多的关注,纯的Sb相变材料可以避免可逆结晶熔化过程中元素迁移引起的组分偏差,从而有利于相变存储器的循环寿命。然而,纯的Sb薄膜呈现的是一种爆炸式的结晶方式,这种结晶方式的出现导致薄膜的非晶态热稳定性差,结晶温度较低,仅不到65℃,而研究最广泛的GST(Ge2Sb2Te5)相变温度在160℃。此外,结晶Sb薄膜较低的电阻率都会导致相变存储器出现较大的电流和较高的功率。

发明内容

本发明所要解决的技术问题是提供一种具有较高的结晶温度和较强的十年数据保持力,较快结晶速度,较好的热稳定性,以及较大的非晶和晶态电阻率的用于相变存储器的Sb-Si3N4薄膜材料及其制备方法,该方法成本低,工艺可控性强,易于大规模生产。

本发明解决上述技术问题所采用的技术方案为:一种用于相变存储器的Sb-Si3N4薄膜材料,其化学结构式为Sbx(Si3N4)100-x,其中Sb的原子数百分含量为15≤x≤50。

优选的,所述的相变薄膜材料的化学结构式为Sb15(Si3N4)85

上述用于相变存储器的Sb-Si3N4薄膜材料的制备方法,采用高纯度圆块状Sb和Si3N4作为靶材,使用磁控溅射仪器,通过双靶共同溅射,通入高纯度氩气作为工作气体,以硅片或石英片作为衬底材料进行表面沉积,具体步骤如下:

(1)分别将Si3N4圆块金属化合物靶材和Sb圆块金属靶材背面与一块直径相同、厚度为1mm的铜片完全贴合,制作为磁控溅射镀膜靶材,将Sb靶材安装在磁控直流溅射靶中,将Si3N4安装在磁控射频溅射靶中;

(2)将石英片或者硅片衬底材料依次放入去离子水中和无水乙醇中超声清洗后取出,用高纯度氮气吹干,放入溅射腔室;

(3)将溅射室进行抽真空直至溅射室真空度达到6×10-4Pa时,通入高纯度氩气,控制进气速率为50ml/min,使溅射室内的气压达到溅射所需的起辉气压0.3Pa;

(4)开启直流电源,调整Sb直流溅射功率为10~20W;打开射频电源,调整Si3N4靶的射频功率为30~60W,待光辉稳定后开始在室温下镀膜,共溅射30min,得到用于相变存储器的Sb-Si3N4薄膜材料,其化学结构式为Sbx(Si3N4)100-x,其中Sb的原子数百分含量为15≤x≤50。

优选的,所述的Sb靶材和所述的Si3N4靶材的纯度均为99.99%。

优选的,将步骤(4)得到的沉积态Sb-Si3N4薄膜材料放入快速退火炉中,在通入高纯度氮气的氛围下,迅速升温至180~330℃下退火,即可得到热处理后的用于相变存储器的Sb-Si3N4薄膜材料。

与现有技术相比,本发明的优点在于:本发明一种用于相变存储器的Sb-Si3N4薄膜材料及其制备方法,该相变薄膜材料的化学结构式为Sbx(Si3N4)100-x,其中0<x<50。该薄膜的结晶温度为110~210℃;测试结构表明,结晶温度、晶态与非晶态电阻随着Si3N4含量的增加线性增加,非晶电阻在104~106Ω,晶态电阻103~104Ω;10年数据保存力的温度经测试为8.52-120.55℃。薄膜晶态电阻的增加会有利于PCM的功耗的降低。本发明生产成本低,重复性好,工艺可控性强,制备得到的Sb-Si3N4薄膜材料不仅具有组分误差小、附着强度高、膜质均匀致密的优点,而且可以根据调控组分调节结晶温度,热稳定性较好,结晶温度快,较大的晶态/非晶态电阻率,可以用于工业化大规模制备大面积相变薄膜从而可以满足未来相变存储器存储材料的应用需求。

附图说明

图1为不同组分的Sbx(Si3N4)100-x薄膜方块电阻随温度变化关系曲线;

图2为不同组分的Sbx(Si3N4)100-x薄膜的数据保持力计算结果图;

图3为组分(Sb)15(Si3N4)85薄膜的相对于温度的结晶度导数图;

图4为组分(Sb)15(Si3N4)85薄膜的Ozawa示意图;

图5为不同组分的Sbx(Si3N4)100-x薄膜在沉积态下的X射线衍射图谱;

图6为不同组分的Sbx(Si3N4)100-x薄膜在180℃下退火后的X射线衍射图谱;

图7为不同组分的Sbx(Si3N4)100-x薄膜在250℃下退火后的X射线衍射图谱;

图8为不同组分的Sbx(Si3N4)100-x薄膜在330℃下退火后的X射线衍射图谱;

图9为不同组分的Sbx(Si3N4)100-x薄膜在沉积态下的拉曼衍射图谱;

图10为不同组分的Sbx(Si3N4)100-x薄膜在180℃下退火后的拉曼衍射图谱;

图11为不同组分的Sbx(Si3N4)100-x薄膜在250℃下退火后的拉曼衍射图谱;

图12为不同组分的Sbx(Si3N4)100-x薄膜在330℃下退火后的拉曼衍射图谱;

图13为组分 (Sb)15(Si3N4)85薄膜在300℃退火后的XPS结果图谱;

图14为不同组分的Sbx(Si3N4)100-x薄膜的原子结构演变结果图。

具体实施方式

以下结合附图实施例对本发明作进一步详细描述。

一、具体实施例

一种用于相变存储器的Sb-Si3N4薄膜材料,其化学结构式为Sbx(Si3N4)100-x,其中Sb的原子数百分含量为15≤x≤50,该材料结晶温度在110~210℃之间,非晶态电阻在104~106Ω,晶态电阻101~103Ω。其制备方法为:使用高纯度圆块Sb和Si3N4材料作为靶材,采用磁控溅射装置,双靶同时溅射,通入高纯度氩气作为工作气体,以石英片或硅片作为衬底材料进行表面积沉积,具体步骤如下:

(1)将Si3N4圆块靶材和Sb圆块靶材背面完全贴合一块与靶材直径形同的圆形铜片,铜片厚度约为1mm,制得磁控溅射镀膜靶材;将Sb靶材安装在直流溅射靶中,将Si3N4安装在射频溅射靶中;

(2)将石英片或者硅片放入去离子水中超声清洗15分钟,再放入无水乙醇中超声清洗15分钟,取出后用高纯氮气吹干,作为衬底,放入溅射腔室;

(3)将溅射腔室进行抽真空直至真空度达到6×10-4Pa时,通入高纯度氩气,控制进气速率为50ml/min,使溅射室内的气压达到溅射所需的起辉气压0.3Pa;

(4)开启直流电源,调整Sb直流溅射功率为10~20W,打开射频电源,调整Si3N4靶的射频功率为30~60W;待光辉稳定后开始在室温下镀膜,共溅射时间约为30min,得到厚度约为150nm左右的Sb-Si3N4相变薄膜材料。将上述步骤(4)得到的沉积态Sb-Si3N4薄膜材料放入快速退火炉中,在通入氮气的条件下,迅速升温至180~330℃下退火,即可得到热处理后的Sb-Si3N4相变薄膜材料。

上述所用的磁控溅射装置是由中国科学院沈阳科学仪器研制中心有限公司制造的JGP-450磁控溅射沉积系统。采用的溅射靶材均为纯度99.99%,尺寸Φ50×3mm。在圆块状Si3N4与Sb背面粘贴1mm厚的直径相同的铜片,以解决玻璃靶材在溅射过程中散热问题。

实施例1

一种用于相变存储器的Sb-Si3N4薄膜,其制备方法如下:

(1)使用Si3N4和Sb双靶同时溅射镀膜:将Sb靶材安装在磁控直流溅射靶中,将Si3N4靶材安装在磁控射频溅射靶中;对溅射腔室进行抽真空处理,当溅射腔室内真空度达到6×10-4Pa时,向室内充入高纯氩气,氩气流量为50.0ml/min,直至腔室内达到溅射所需的起辉气压0.3Pa;开启射频电源,待起辉稳定后,调节Sb所在的直流溅射靶功率为10W,Si3N4靶材所在磁控射频溅射功率为60W,待功率稳定后,开启衬底转盘自转并将自转速率设定为5rpm,打开衬底下方的挡板,溅射30min后得到沉积态的Sb-Si3N4薄膜;

(2)将步骤(1)得到的沉积态相变存储薄膜样品放入快速退火炉中,在通入氮气的条件下,迅速升温至180~330℃下退火,得到热处理后的Sb-Si3N4相变薄膜材料。退火期间通入高纯氮气的作用是为避免薄膜在高温下发生氧化。

上述实施例1制备得到的Sb-Si3N4薄膜组分由X射线能谱分析法(EDS)测得,薄膜厚度由台阶仪测得,测试结果为:薄膜组分为(Sb)15(Si3N4)85,薄膜厚度为150nm。该薄膜相应的结晶温度为210℃,非晶电阻为2×105Ω,晶态电阻为2.3×102Ω;10年数据保存力的温度经测试为120.55℃。

实施例2

同实施例1,其不同之处在于将Sb所在的直流溅射靶的功率不变仍为10W,Si3N4所在的射频靶射频功率调节为50W。

上述实施例2制备的Sb-Si3N4薄膜组分有X射线能谱分析法(EDS)测得,薄膜厚度由台阶仪测得,测试结果为:薄膜组分为(Sb)20(Si3N4)80,薄膜厚度为150nm。该薄膜相应的结晶温度为200℃,非晶电阻为1.4×105Ω,晶态电阻为1×102Ω;10年数据保存力的温度经测试为94.91℃。

实施例3

同实施例1,其不同之处在于将Sb所在的直流溅射靶的功率不变仍为10W,Si3N4所在的射频靶射频功率调节为35W。

上述实施例3制备的Sb-Si3N4薄膜组分有X射线能谱分析法(EDS)测得,薄膜厚度由台阶仪测得,测试结果为:薄膜组分为(Sb)40(Si3N4)60,薄膜厚度为150nm。该薄膜相应的结晶温度为135℃,非晶电阻为1.2×105Ω,晶态电阻为2×102Ω;10年数据保存力的温度经测试为56.53℃。

实施例4

同实施例1,其不同之处在于将Sb所在的直流溅射靶的功率调节为20W,Si3N4所在的射频靶射频功率调节为35W。

上述实施例4制备的Sb-Si3N4薄膜组分有X射线能谱分析法(EDS)测得,薄膜厚度由台阶仪测得,测试结果为:薄膜组分为(Sb)45(Si3N4)55,薄膜厚度为150nm。该薄膜相应的结晶温度为125℃,非晶电阻为1.2×104Ω,晶态电阻为1.9×101Ω;10年数据保存力的温度经测试为39.64℃。

实施例5

同实施例1,其不同之处在于将Sb所在的直流溅射靶的功率调节为20W,Si3N4所在的射频靶射频功率调节为30W。

上述实施例5制备的Sb-Si3N4薄膜组分有X射线能谱分析法(EDS)测得,薄膜厚度由台阶仪测得,测试结果为:薄膜组分为(Sb)50(Si3N4)50,薄膜厚度为150nm。该薄膜相应的结晶温度为110℃,非晶电阻为1×104Ω,晶态电阻为1.8×101Ω;10年数据保存力的温度经测试为8.52℃。

二、实验结果分析

对上述实施例制备的Sbx(Si3N4)100-x薄膜进行性能测试,图1和图2为原位电阻性能测试结果。图1为不同薄膜组分的薄膜材料在50℃/min升温速率下方块电阻与温度的关系。可以看出,掺杂后越高的Sb含量会使结晶温度、非晶态和晶态电阻率均增加,由此可以得出材料掺杂后热稳定性能增加,有利于于存储器后能够相应减低功耗。另外,图1也可以看出,电阻的降低随着Si3N4浓度的增加而减慢,这表明Si3N4的掺杂会减慢Sb薄膜的结晶过程。从图2可以看出数据保持力也随着掺杂浓度相应变化,在目前掺含量在Sb占15%的情况下,(Sb)15(Si3N4)85薄膜的数据保持力为120.55℃,远高于GST的82.1℃,进一步说明了掺杂Si3N4会使Sb-Si3N4薄膜热稳定增加。

图3是(Sb)15(Si3N4)85薄膜的相对于温度的结晶度导数图。峰值强度随着Si3N4含量的增加而降低,这表明随着Si3N4的加入,结晶速率降低。这表明Si3N4充当阻碍Sb晶体生长的杂质。

图4是(Sb)15(Si3N4)85薄膜的Ozawa示意图。结晶机理有关的动力学指数n随温度升高而降低表明反应的成核速率或生长尺寸降低。插图中整个样品的平均n值比1.5高,这表明(Sb)15(Si3N4)85薄膜的成核过程主要是晶化过程。

图5、图6、图7和图8分别是不同组分在常温下,180℃,250℃和330℃下退火后的X射线衍射图谱。可以看出,与没有的结晶峰沉积态的非晶态膜相比,经过高温退火后的掺杂后的薄膜出现了由Sb的菱形相引起的特征衍射峰Sb(012),并且在180℃下该衍射峰随着Si3N4掺杂浓度的增加而降低,表明样品的无序度随Si3N4浓度的增加而增加。高无序度将导致样品需要高能量进行结晶,从而提高了热稳定性。图7和8中,随着更高的250℃和330℃退火温度下,Sb(012)衍射峰在所有样品均观察到,且没有出现新的峰,表明所有样品均结晶。通过Scherrer公式计算,Sb50(Si3N4)50,(Sb)45(Si3N4)55,(Sb)40(Si3N4)60,(Sb)20(Si3N4)80和(Sb)15(Si3N4)85薄膜的Sb(012)晶粒在330℃时分别为57.4nm,36.5nm,34.22、16.9nm和14.9nm。随着晶粒尺寸的减小,引入了许多晶粒边界。因此,更多的载流子散射发生在边界处,导致抗结晶性增加。没有在所有Sbx(Si3N4)100-x膜上观察到Si3N4的特征衍射峰,表明掺杂的Si3N4以非晶态存在。

图9、图10、图11和图12为不同组分在常温下,180℃,250℃和330℃下的拉曼衍射图。对于所有沉积的薄膜,由于所沉积样品的长距离无序Sb-Sb键的共振,一个强峰出现在139 cm-1处,凸带宽谱覆盖100-180cm-1区域(参见图9)。当薄膜在180℃退火15分钟时,由于热稳定性显着提高,Sb15(Si3N4)85 薄膜和Sb20(Si3N4)80薄膜光谱不变。非晶态到晶体的相变导致(Sb)40(Si3N4)60,Sb20(Si3N4)80和Sb15(Si3N4)85薄膜在139cm-1处的峰被分为两个峰,分别为在110 cm-1处的峰B和在150 cm-1处的峰C,峰B和C分别被认为是Sb相的A7结构的Eg模式和Alg模式,对应于Sb-Sb键振动(参见图10)。在250℃下,Sb15(Si3N4)85 和Sb20(Si3N4)80样品的峰A消失,出现峰B和C。在330℃下,B峰从110 cm-1移到119 cm-1,C峰从150 cm-1移到151 cm-1。值得注意的是,B峰的移动C峰在330℃时的峰归因于Sb的部分结晶。从180℃到330℃,在相同温度下, 所有膜的组分的B和C峰强度都随着Si3N4浓度的增加而降低,这表明添加Si3N4会抑制Sb的结晶。

图13为组分为Sb15(Si3N4)85薄膜在300℃退火后的XPS结果图谱。图13(a)中在397.3eV处的N 1s峰的结合能是典型的氮化物结合能,其归因于Si3N4。这意味着引入Sb-Si3N4膜的N主要以非晶态Si3N4的形式存在,并且不与Sb形成化合键。插图中的Si 2p光谱也可以确认薄膜中存在非晶Si3N4。由图13(b)可以看到在537.6eV和528.2eV处的峰对应于元素Sb的Sb 3d3/2和3d5/2峰,表明在结晶的Sb-Si3N4薄膜中Sb元素不与氮化物形成化学键,因此在薄膜的结晶状态下无法检测到Sb-N键。

图14为不同组分的Sbx(Si3N4)100-x薄膜的原子结构演变结果图;由于Si3N4材料的化学稳定性,将Si3N4添加到Sb中会导致形成纳米复合结构,从而破坏了均匀Sb的长期顺序的结构(参见图14(a)),并限制了其纳米尺寸。Si3N4以物理包裹的形式分布在Sb周围(参加图14(b))。它抑制了Sb的生长,因此提高了相变温度。

上述说明并非对本发明的限制,本发明也并不限于上述举例。本技术领域的普通技术人员在本发明的实质范围内,做出的变化、改型、添加或替换,也应属于本发明的保护范围。

【EN】

Sb-Si for phase change memory3N4Thin film material and preparation method thereof

Technical Field

The invention relates to the field of phase change memory materials, in particular to Sb-Si for a phase change memory3N4A film material and a preparation method thereof.

Background

Nowadays, the wide application of electronic products has prompted the continuous development of memories, and compared with the current flash memory in the non-volatile memory market, the Phase Change Memory (PCM) not only solves the problem of low cycle number (-10)6) And longer writing time (>10 us), also showing significant advantages in terms of large capacity, high density, high speed, low power consumption, low cost, etc., PCM memory cells have proven to be free of any physical limitations prior to the 5nm technology node. In addition, the phase change memory has the advantages of low manufacturing cost, simple manufacturing process, high storage density, low power consumption, strong data storage capacity and the like, so that the phase change memory attracts attention and is considered to be one of the most promising nonvolatile memories. The phase change memory can be rapidly and reversibly switched between the crystalline state and the amorphous state in a sub-nanosecond range under the stimulation of electricity or light, has excellent non-volatility, excellent durability and high contrast property between the two states, so that the phase change memory is widely used in military and civil fields and has extremely high research value in the fields of aerospace and the like. The principle of the phase change memory is that the storage medium material is mutually converted between a crystalline state (low resistance) and an amorphous state (high resistance) by using electric pulses (heat) to realize writing and erasing of information, reading of the information is realized by measuring the change of the resistance, and joule heat is inevitably generated in the process, so that the thermal stability of the phase change material is very important for the research and development of the phase change memory.

In the phase change material, antimony (Sb) has a lower melting point and a higher crystallization rate, which draws more and more attention, and the pure Sb phase change material can avoid component deviation caused by element migration in a reversible crystallization melting process, thereby being beneficial to the cycle life of the phase change memory. However, pure Sb thin films exhibit an explosive crystallization mode, which results in poor amorphous thermal stability of the thin films and a low crystallization temperature of less than 65 ℃, and the most widely studied GST (Ge) is2Sb2Te5) The phase transition temperature was 160 ℃. In addition, the lower resistivity of the crystallized Sb thin film results in higher current and higher power in the phase change memory.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a catalyst with higher crystallization temperature, stronger ten-year data retention, higher crystallization speed, better thermal stability and larger amorphous and crystalline resistivitySb-Si for phase change memory3N4The film material and the preparation method thereof have the advantages of low cost, strong process controllability and easy large-scale production.

The technical scheme adopted by the invention for solving the technical problems is as follows: Sb-Si for phase change memory3N4A thin film material with a chemical structural formula of Sbx(Si3N4)100-xWherein the atomic number percentage of Sb is more than or equal to 15 and less than or equal to 50.

Preferably, the chemical structural formula of the phase-change film material is Sb15(Si3N4)85

The Sb-Si for the phase change memory3N4The preparation method of the film material adopts high-purity round Sb and Si3N4The method is characterized in that a magnetron sputtering instrument is used as a target material, double targets are sputtered together, high-purity argon is introduced to be used as working gas, a silicon wafer or a quartz wafer is used as a substrate material to carry out surface deposition, and the method specifically comprises the following steps:

(1) respectively adding Si3N4The back surfaces of the round metal compound target material and the Sb round metal target material are completely attached to a copper sheet with the same diameter and the thickness of 1mm to manufacture a magnetron sputtering coating target material, the Sb target material is arranged in a magnetron direct current sputtering target, and Si is arranged in the magnetron direct current sputtering target3N4The magnetic control radio frequency sputtering target is arranged in the magnetic control radio frequency sputtering target;

(2) sequentially putting a quartz plate or a silicon wafer substrate material into deionized water and absolute ethyl alcohol for ultrasonic cleaning, then taking out, drying by using high-purity nitrogen, and putting into a sputtering chamber;

(3) vacuumizing the sputtering chamber until the vacuum degree of the sputtering chamber reaches 6 multiplied by 10-4When Pa, introducing high-purity argon, and controlling the gas inlet rate to be 50ml/min to enable the gas pressure in the sputtering chamber to reach the starting glow pressure of 0.3Pa required by sputtering;

(4) starting a direct current power supply, and adjusting the direct current sputtering power of Sb to be 10-20W; turning on the radio frequency power supply and adjusting Si3N4The radio frequency power of the target is 30-60W, coating is carried out at room temperature after the radiance is stabilized, co-sputtering is carried out for 30min, and Sb-Si for the phase change memory is obtained3N4A thin film material with a chemical structural formula of Sbx(Si3N4)100-xWherein the atomic number percentage of Sb is more than or equal to 15 and less than or equal to 50.

Preferably, the Sb target material and the Si are3N4The purity of the target material is 99.99 percent.

Preferably, the Sb-Si in the deposition state obtained in the step (4)3N4The film material is placed into a rapid annealing furnace, and annealing is carried out when the temperature is rapidly increased to 180-330 ℃ under the atmosphere of introducing high-purity nitrogen, so that the thermally treated Sb-Si for the phase change memory can be obtained3N4A film material.

Compared with the prior art, the invention has the advantages that: the invention relates to Sb-Si for a phase change memory3N4The chemical structural formula of the phase-change film material is Sbx(Si3N4)100-xWherein 0 is<x<50. The crystallization temperature of the film is 110-210 ℃; the test structure shows that the crystallization temperature, crystalline state and amorphous state resistance are along with Si3N4The content increases linearly, and the amorphous resistance is 104~106Omega, crystalline resistance 103~104Omega; the temperature for data retention was tested at 8.52-120.55 ℃ for 10 years. An increase in the thin film crystalline resistance may be beneficial in reducing the power consumption of the PCM. The invention has the advantages of low production cost, good repeatability and strong process controllability, and the prepared Sb-Si is3N4The film material not only has the advantages of small component error, high adhesion strength and uniform and compact film quality, but also can adjust the crystallization temperature according to the regulation and control components, has better thermal stability, high crystallization temperature and larger crystalline/amorphous resistivity, and can be used for preparing large-area phase change films in an industrialized and large scale so as to meet the application requirements of future phase change memory storage materials.

Drawings

FIG. 1 shows Sb with different compositionsx(Si3N4)100-xThe square resistance of the film changes with the temperature;

FIG. 2 shows Sb in different compositionsx(Si3N4)100-xA graph of the calculated data retention of the film;

FIG. 3 shows the components (Sb)15(Si3N4)85A plot of the crystallinity derivative of the film with respect to temperature;

FIG. 4 shows the components (Sb)15(Si3N4)85Ozawa schematic of film;

FIG. 5 shows Sb with different compositionsx(Si3N4)100-xX-ray diffraction pattern of the film in deposition state;

FIG. 6 shows Sb with different compositionsx(Si3N4)100-xAn X-ray diffraction pattern of the film after annealing at 180 ℃;

FIG. 7 shows Sb with different compositionsx(Si3N4)100-xAn X-ray diffraction pattern of the film after annealing at 250 ℃;

FIG. 8 shows Sb with different compositionsx(Si3N4)100-xAn X-ray diffraction pattern of the film after annealing at 330 ℃;

FIG. 9 shows Sb with different compositionsx(Si3N4)100-xRaman diffraction spectrum of the film in deposition state;

FIG. 10 shows Sb of different compositionsx(Si3N4)100-xA Raman diffraction spectrum of the film after annealing at 180 ℃;

FIG. 11 shows Sb with different compositionsx(Si3N4)100-xA Raman diffraction spectrum of the film after annealing at 250 ℃;

FIG. 12 shows Sb with different compositionsx(Si3N4)100-xA Raman diffraction spectrum of the film after annealing at 330 ℃;

FIG. 13 shows components (Sb)15(Si3N4)85XPS result spectrum of film after annealing at 300 ℃;

FIG. 14 shows Sb with different compositionsx(Si3N4)100-xAnd (5) an atomic structure evolution result graph of the film.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

Detailed description of the preferred embodiments

Sb-Si for phase change memory3N4A thin film material with a chemical structural formula of Sbx(Si3N4)100-xWherein x is more than or equal to 15 and less than or equal to 50, the crystallization temperature of the material is between 110 and 210 ℃, and the amorphous resistance is 104~106Omega, crystalline resistance 101~103Omega. The preparation method comprises the following steps: using high purity pellets Sb and Si3N4The material is used as a target material, a magnetron sputtering device is adopted, double targets are sputtered simultaneously, high-purity argon is introduced as working gas, a quartz plate or a silicon wafer is used as a substrate material for surface area deposition, and the specific steps are as follows:

(1) mixing Si3N4Completely attaching a round copper sheet with the same diameter as the target material to the back surfaces of the round block target material and the Sb round block target material, wherein the thickness of the copper sheet is about 1mm, and preparing the magnetron sputtering coating target material; mounting Sb target material in a DC sputtering target, and mounting Si3N4Mounting in a radio frequency sputtering target;

(2) putting a quartz plate or a silicon wafer into deionized water for ultrasonic cleaning for 15 minutes, then putting the quartz plate or the silicon wafer into absolute ethyl alcohol for ultrasonic cleaning for 15 minutes, taking out the quartz plate or the silicon wafer, drying the quartz plate or the silicon wafer by using high-purity nitrogen as a substrate, and putting the substrate into a sputtering chamber;

(3) vacuumizing the sputtering chamber until the vacuum degree reaches 6 multiplied by 10-4When Pa, introducing high-purity argon, and controlling the gas inlet rate to be 50ml/min to enable the gas pressure in the sputtering chamber to reach the starting glow pressure of 0.3Pa required by sputtering;

(4) starting a direct current power supply, adjusting Sb direct current sputtering power to 10-20W, starting a radio frequency power supply, and adjusting Si3N4The radio frequency power of the target is 30-60W; starting to coat at room temperature after the brilliance is stable, and carrying out co-sputtering for about 30min to obtain Sb-Si with the thickness of about 150nm3N4A phase change film material. The Sb-Si in the deposition state obtained in the step (4) is added3N4The film material is put into a rapid annealing furnace, under the condition of introducing nitrogen,rapidly heating to 180-330 ℃ for annealing to obtain the thermally treated Sb-Si3N4A phase change film material.

The magnetron sputtering apparatus used in the above was a JGP-450 magnetron sputtering deposition system manufactured by Shenyang scientific instruments research center, Inc., of Chinese academy of sciences. The adopted sputtering target materials have the purity of 99.99 percent and the size phi of 50 multiplied by 3 mm. In the shape of a round block of Si3N4Copper sheets with the thickness of 1mm and the same diameter are adhered to the back of Sb so as to solve the problem of heat dissipation of the glass target material in the sputtering process.

Example 1

Sb-Si for phase change memory3N4The preparation method of the film comprises the following steps:

(1) using Si3N4And Sb double-target simultaneous sputtering coating: sb target material is arranged in a magnetic control direct current sputtering target, and Si is arranged3N4The target material is arranged in a magnetic control radio frequency sputtering target; vacuumizing the sputtering chamber until the vacuum degree in the sputtering chamber reaches 6 x 10-4When Pa is needed, filling high-purity argon into the chamber, wherein the flow of the argon is 50.0ml/min until the glow starting pressure required by sputtering in the chamber is 0.3 Pa; starting a radio frequency power supply, and after the starting is stable, adjusting the power of the direct current sputtering target where Sb is positioned to be 10W and Si3N4The magnetron radio frequency sputtering power of the target material is 60W, after the power is stable, the substrate turntable is started to rotate and the rotation speed is set to 5rpm, the baffle below the substrate is opened, and the Sb-Si in a deposition state is obtained after sputtering for 30min3N4A film;

(2) putting the deposition phase change storage film sample obtained in the step (1) into a rapid annealing furnace, rapidly heating to 180-330 ℃ under the condition of introducing nitrogen, and annealing to obtain the thermally treated Sb-Si3N4A phase change film material. The function of introducing high-purity nitrogen during annealing is to avoid the oxidation of the film at high temperature.

Sb-Si prepared in the above example 13N4The film components are measured by X-ray energy spectrometry (EDS), the film thickness is measured by a step profiler, and the test results are as follows: the film composition is (Sb)15(Si3N4)85The film thickness was 150 nm. The film has a crystallization temperature of 210 deg.C and an amorphous resistance of 2 × 105Omega, crystalline resistance 2.3X 102Omega; the temperature for data retention was tested to be 120.55 ℃ over 10 years.

Example 2

The difference from example 1 is that the power of the DC sputtering target in which Sb is present is 10W and Si is not changed3N4The RF power of the RF target is adjusted to 50W.

Sb-Si prepared in the above example 23N4The film components are measured by an X-ray energy spectrum analysis method (EDS), the film thickness is measured by a step profiler, and the test result is as follows: the film composition is (Sb)20(Si3N4)80The film thickness was 150 nm. The film has a crystallization temperature of 200 deg.C and an amorphous resistance of 1.4 × 105Ω, crystalline resistance 1 × 102Omega; the temperature for data retention was tested to be 94.91 ℃ over 10 years.

Example 3

The difference from example 1 is that the power of the DC sputtering target in which Sb is present is 10W and Si is not changed3N4The RF power of the RF target is adjusted to 35W.

Sb-Si prepared in the above example 33N4The film components are measured by an X-ray energy spectrum analysis method (EDS), the film thickness is measured by a step profiler, and the test result is as follows: the film composition is (Sb)40(Si3N4)60The film thickness was 150 nm. The film has a crystallization temperature of 135 deg.C and an amorphous resistance of 1.2 × 105Omega, crystalline resistance 2X 102Omega; the temperature at which data retention was measured for 10 years was 56.53 ℃.

Example 4

The difference from example 1 is that the power of the DC sputtering target containing Sb was adjusted to 20W, Si3N4The RF power of the RF target is adjusted to 35W.

Sb-Si prepared in the above example 43N4The film composition is measured by X-ray energy spectrometry (EDS), and the film thickness is measured by a step profilerThe test results were obtained as follows: the film composition is (Sb)45(Si3N4)55The film thickness was 150 nm. The film has a crystallization temperature of 125 deg.C and an amorphous resistance of 1.2 × 104Omega, crystalline resistance 1.9X 101Omega; the temperature at which data retention was measured for 10 years was 39.64 ℃.

Example 5

The difference from example 1 is that the power of the DC sputtering target containing Sb was adjusted to 20W, Si3N4The RF power of the RF target is adjusted to 30W.

Sb-Si prepared in the above example 53N4The film components are measured by an X-ray energy spectrum analysis method (EDS), the film thickness is measured by a step profiler, and the test result is as follows: the film composition is (Sb)50(Si3N4)50The film thickness was 150 nm. The film has a crystallization temperature of 110 deg.C and an amorphous resistance of 1 × 104Omega, crystalline resistance 1.8X 101Omega; the temperature for data retention was tested to be 8.52 ℃ for 10 years.

Second, analysis of experimental results

Sb prepared in the above examplesx(Si3N4)100-xThe film was tested for performance, and fig. 1 and 2 are in-situ resistance performance test results. FIG. 1 is a graph of sheet resistance versus temperature for film materials of different film compositions at a heating rate of 50 deg.C/min. It can be seen that the higher the Sb content after doping, the higher the crystallization temperature, the amorphous state and the crystalline state resistivity, and thus the thermal stability of the doped material can be increased, which is beneficial to reducing the power consumption after the memory. In addition, as can also be seen in FIG. 1, the decrease in resistance is accompanied by Si3N4The increase in concentration slowed down, indicating that Si3N4The doping of (a) slows down the crystallization process of the Sb thin film. It can be seen from FIG. 2 that the data retention also varies with the doping concentration, with the current doping level being 15% Sb (Sb)15(Si3N4)85The data retention of the film was 120.55 deg.C, which is much higher than 82.1 deg.C for GST, further illustrating the doping of Si3N4Sb-Si is caused to be present3N4The film is increased in thermal stability.

FIG. 3 is (Sb)15(Si3N4)85Graph of crystallinity derivative of thin film with respect to temperature. Peak intensity with Si3N4The content decreases with increasing Si, which indicates that with increasing Si3N4With addition of (b), the crystallization rate decreases. This indicates that Si is present3N4Serving as impurities that hinder Sb crystal growth.

FIG. 4 is (Sb)15(Si3N4)85Ozawa schematic of the film. The decrease of the kinetic index n associated with the crystallization mechanism with increasing temperature indicates a decrease in the nucleation rate or growth size of the reaction. The average n value for the entire sample in the inset is higher than 1.5, indicating (Sb)15(Si3N4)85The nucleation process of the film is mainly a crystallization process.

FIGS. 5, 6, 7 and 8 are X-ray diffraction patterns of different compositions after annealing at 180 deg.C, 250 deg.C and 330 deg.C, respectively, at normal temperature. It can be seen that the doped thin film after high temperature annealing exhibited a characteristic diffraction peak Sb (012) due to the rhombohedral phase of Sb, as compared to the amorphous film without the crystalline peak deposition state, and that the diffraction peak was accompanied by Si at 180 deg.C3N4The increase in doping concentration decreased, indicating that the disorder of the sample decreased with Si3N4The concentration increases. High disorder will result in samples requiring high energy to crystallize, thereby improving thermal stability. In fig. 7 and 8, with higher annealing temperatures of 250 ℃ and 330 ℃, the Sb (012) diffraction peak was observed in all samples, and no new peak appeared, indicating that all samples were crystallized. Calculated by the Scherrer formula, Sb50(Si3N4)50,(Sb)45(Si3N4)55,(Sb)40(Si3N4)60,(Sb)20(Si3N4)80And (Sb)15(Si3N4)85The Sb (012) crystal grains of the film were 57.4nm, 36.5nm, 34.22 nm, 16.9nm and 14.9nm at 330 ℃. As the grain size decreases, introduceA plurality of grain boundaries. Therefore, more carrier scattering occurs at the boundary, resulting in increased resistance to crystallization. Not in all Sbx(Si3N4)100-xSi was observed on the film3N4Characteristic diffraction peak of indicating doped Si3N4In the amorphous state.

Fig. 9, 10, 11 and 12 are raman diffraction patterns of different components at 180 ℃, 250 ℃ and 330 ℃ at normal temperature. For all deposited films, a strong peak appears at 139cm due to the resonance of the long disordered Sb-Sb bonds of the deposited samples-1Convex bandwidth spectrum covers 100--1Area (see fig. 9). Sb is remarkably improved due to the thermal stability when the film is annealed at 180 ℃ for 15 minutes15(Si3N4)85 Film and Sb20(Si3N4)80The film spectrum is unchanged. Amorphous to crystalline phase transition results in (Sb)40(Si3N4)60,Sb20(Si3N4)80And Sb15(Si3N4)85The film is 139cm-1The peak is divided into two peaks, each at 110 cm-1Peak B and peak at 150 cm-1The peak C, the peaks B and C are considered to be E of the A7 structure of the Sb phasegMode and AlgMode, corresponding to Sb — Sb bond vibration (see fig. 10). At 250 ℃ Sb15(Si3N4)85 And Sb20(Si3N4)80Peak a of the sample disappeared and peaks B and C appeared. At 330 ℃ the B peak is from 110 cm-1Move to 119 cm-1C peak from 150 cm-1Move to 151 cm-1. Notably, the shift of the B peak the peak at 330 ℃ of the C peak is due to the partial crystallization of Sb. From 180 ℃ to 330 ℃ and at the same temperature, the B and C peak intensities of all film components follow the Si3N4Increase in concentration and decrease, indicating addition of Si3N4The crystallization of Sb is suppressed.

FIG. 13 shows a composition Sb15(Si3N4)85The film is at 300 DEG CXPS results profile after annealing. The binding energy of the N1 s peak at 397.3eV in FIG. 13 (a) is typical of the nitride binding energy, which is attributed to Si3N4. This means that Sb-Si is introduced3N4The N of the film is mainly amorphous Si3N4Exist without forming a bond with Sb. The presence of amorphous Si in the thin film can also be confirmed by the Si 2p spectrum in the inset3N4. It can be seen from FIG. 13 (b) that the peaks at 537.6eV and 528.2eV correspond to Sb 3d of the element Sb3/2And 3d5/2Peak showing Sb-Si in the crystal3N4The Sb element in the thin film does not form a chemical bond with the nitride, and therefore the Sb — N bond cannot be detected in the crystalline state of the thin film.

FIG. 14 shows Sb with different compositionsx(Si3N4)100-xThe atomic structure evolution result of the film is shown; due to Si3N4Chemical stability of the material, Si3N4The addition to Sb results in the formation of a nanocomposite structure, thereby destroying the long-term sequential structure of uniform Sb (see fig. 14 (a)) and limiting its nano-size. Si3N4Distributed around Sb in the form of physical wrapping (see fig. 14 (b)). It inhibits the growth of Sb and thus increases the phase transition temperature.

The above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Those skilled in the art should also realize that changes, modifications, additions and substitutions can be made without departing from the true spirit and scope of the invention.

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