摘要
为有效利用多晶硅纳米薄膜研制MEMS压阻器件,本文对LPCVD多晶硅纳米薄膜应变系数与掺硼浓度的关系进行了研究,并利用扫描电镜和X射线衍射实验分析了薄膜的结构特点.结果表明:在重掺杂情况下,纳米薄膜的应变系数明显大于相同掺杂浓度下单晶硅的应变系数,而且掺杂浓度在2.5×1020cm-3左右时,应变系数具有随掺杂浓度升高而增大的趋势.对这种实验结果依据隧道效应原理进行了理论解释,提出了多晶硅压阻特性的修正模型.
For the purpose of aiding the development of effective MEMS strain sensors using polysilicon nano-film,we investigate the relationship between the B-doped concentration and the gauge factor of LPCVD-grown polysilicon nano-film and analyze the structure of the film via scanning electron photomicrographs and X-ray diffraction-spectra. Experiments show that under a heavy doping condition, the gauge factor of the nano-film is significantly larger than that of monocrystalline silicon with the same doping level, and when the doping concentration is around 2.5 ×10^20cm^-3 , the gauge factor of the film increases with the increase of the doping concentration. These results are explained by the tunneling effect. A modified model of piezoresistive properties for polysilicon is then presented constructively.
关键词
多晶硅
纳米薄膜
压阻特性
隧道效应
应变系数
polysilicon
nano-film
piezoresistive property
tunnel effect
gauge factor
