多晶硅薄膜晶体结构对薄膜压阻效应的影响

The Influence of Polysilicon Thin Film Crystal Structure Upon the Film Piezoresistive Effect

本文研究了LPCVD多晶硅薄膜晶体结构对薄膜压阻效应的影响,通过改变淀积温度和膜厚得到晶体结构不同的薄膜,经硼离子注入掺杂,杂质浓度均为10^(25)/m^3用X 射线衍射法分析了薄膜晶体结构,悬梁实验测出薄膜应变系数GF 随淀积温度和膜厚的变化。理论分析表明,GF 不仅随晶粒度单调增加,而且与织构情况密切相关,不同织构压阻效应大小不同,〈100〉结构对薄膜压阻效应影响很大。理论结果较好地解释了薄膜GF 与淀积温度和膜厚的实验曲线.

In this paper,the influence of the crystal structure of LPCVD polysilicon thinfilm upon the film piezoresistive effect has been researched.Changing the depositiontemperature and the film thickness,the different crystal structures of the film have beenobtained.The doping concentration is 10~25 ((?)/m)~3 in all the films by boron ionimplantation.The thin film structure has been analysed by means of the x—raydiffraction;the variations of polysilicon thin film Gauge Factor(GF)with depositiontemperature and film thickness have been studied by beam deflection method.The re-sult of theoretical analysis has shown that the film GF not only monotonously increaseswith crystalline grain size,but also closely related to the texture state,the piezoresistiveeffect is different for the distinct textures and the piegoresisitive effect of the〈100〉struc-ture in the thin film is the greatest.The experimental curves of thin film GF versus thedeposition temperature and film thickness have been explained theoretically.