等离子增强化学气相沉积制备氮化硅薄膜的工艺优化与性能  

Process optimization and performance of plasma enhanced chemical vapor deposition for preparing silicon nitride thin films

作　　者：张志坤 占勤[1] 窦志昂 白敬元 杨洪广[1] ZHANG Zhi-kun;ZHAN Qin;DOU Zhi-ang;BAI Jing-yuan;YANG Hong-guang(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《材料热处理学报》2023年第8期149-155,共7页Transactions of Materials and Heat Treatment

基　　金：中核集团英才基金(219601)。

摘　　要：采用等离子增强化学气相沉积方法在p型<100>硅片沉积氮化硅薄膜,通过椭偏仪和缓冲氧化物刻蚀液(BOE)溶解实验来表征薄膜的均匀性与致密度,研究了射频功率、腔室气压、气体流量比和衬底温度4个工艺参数对氮化硅薄膜性能的影响。结果表明:在60~100 W范围内,射频功率越大,氮化硅薄膜生长速率越快;腔室气压在130 Pa时有利于形成均匀性好、结构致密的氮化硅薄膜。硅烷/氨气气体流量比例较低时,提高流量比可以提高薄膜的致密度,但比例超过1.4后致密度几乎不再变化;衬底温度在200~300℃时,衬底温度越高,薄膜的生长速率越低,致密度越高。最优的工艺参数为:射频功率100 W、腔室气压130 Pa、硅烷流量280 mL/min、氨气流量10 mL/min、衬底温度300℃,此时氮化硅薄膜的生长速率为16.3 nm/min,均匀性为0.07%,折射率为2.1,溶解速率为0.42 nm/s。The plasma enhanced chemical vapor deposition method was used to deposit silicon nitride thin films on p-type<100>silicon wafers.The uniformity and compactness of the films were characterized through spectroscopic ellipsometry(SE)and buffered oxide etching(BOE)solution dissolution experiments.The effects of four process parameters,including radio frequency(RF)power,chamber pressure,gas flow ratio and substrate temperature,on the properties of the silicon nitride thin films were studied.The results show that in the range of 60-100 W,the higher the RF power,the faster the growth rate of the silicon nitride thin films.A chamber pressure of 130 Pa is conducive to the formation of uniform and dense silicon nitride thin films.When the flow rate ratio of silane/ammonia gas is low,increasing the flow rate ratio can increase the compactness of the film,but the compactness hardly changes when the ratio exceeds 1.4.When the substrate temperature is between 200-300℃,the higher the substrate temperature,the lower the growth rate of the thin films and the higher the compactness.The optimal process parameters are:RF power of 100 W,chamber pressure of 130 Pa,silane flow rate of 280 mL/min,ammonia flow rate of 10 mL/min,substrate temperature of 300℃.The growth rate of the silicon nitride thin films prepared by the optimal process parameters is 16.3 nm/min,uniformity is 0.07%,refractive index is 2.1,and dissolution rate is 0.42 nm/s.

关 键 词：等离子增强化学气相沉积 氮化硅 致密度 均匀性 

分 类 号：TG174.44[金属学及工艺—金属表面处理]