Low-thermal-budget electrically active thick polysilicon for CMOS-First MEMS-last integration  

作　　者：Aron Michael Ian Yao-Hsiang Chuang Chee Yee Kwok Kazuo Omaki 

机构地区：[1]UNSW,Sydney,NSW 2052,Australia

出　　处：《Microsystems & Nanoengineering》2024年第3期395-407,共13页微系统与纳米工程（英文）

基　　金：support received from the School of Electrical Engineering&Telecommunications(EE)and UNSW Sydney.

摘　　要：Low-thermal-budget,electrically active,and thick polysilicon films are necessary for building a microelectromechanical system(MEMS)on top of a complementary metal oxide semiconductor(CMOS).However,the formation of these polysilicon films is a challenge in this field.Herein,for the first time,the development of in situ phosphorus-doped silicon films deposited under ultrahigh-vacuum conditions(~10^(−9)Torr)using electron-beam evaporation(UHVEE)is reported.This process results in electrically active,fully crystallized,low-stress,smooth,and thick polysilicon films with low thermal budgets.The crystallographic,mechanical,and electrical properties of phosphorus-doped UHVEE polysilicon films are studied.These films are compared with intrinsic and boron-doped UHVEE silicon films.Raman spectroscopy,X-ray diffraction(XRD),transmission electron microscopy(TEM)and atomic force microscopy(AFM)are used for crystallographic and surface morphological investigations.Wafer curvature,cantilever deflection profile and resonance frequency measurements are employed to study the mechanical properties of the specimens.Moreover,resistivity measurements are conducted to investigate the electrical properties of the films.Highly vertical,high-aspectratio micromachining of UHVEE polysilicon has been developed.A comb-drive structure is designed,simulated,fabricated,and characterized as an actuator and inertial sensor comprising 20-μm-thick in situ phosphorus-doped UHVEE films at a temperature less than 500℃.The results demonstrate for the first time that UHVEE polysilicon uniquely allows the realization of mechanically and electrically functional MEMS devices with low thermal budgets.

关 键 词：BUDGET THICK THERMAL 

分 类 号：TN43[电子电信—微电子学与固体电子学]