用于热机械微纳加工的掺Al多晶硅加热器

摘要

针对热机械式微纳米结构的加工,提出了一种以掺Al多晶硅为材料,集成于微悬臂梁上的加热器.采用Al诱导退火晶化(AIC)方法,在750 K对Al/a-Si∶H复合薄膜低温晶化18 h,制备出掺Al多晶硅.通过低温退火,使复合薄膜的拉曼特征峰由478 cm-1移至520 cm-1,完成由非晶硅向多晶硅的转变;由四探针仪测得室温下样品的电阻率由退火前的1010 Ω·cm降至16.8×10-3Ω·cm,实现了多晶硅的Al掺杂;在扫描电镜下观测到退火后Al与a-Si∶H层的界限消失并形成一层均匀的薄膜;这些结果表明得到了晶化程度很高的Al掺杂多晶硅.继而研究了掺Al多晶硅与氮化硅悬臂梁的集成工艺,采用微加工方法将掺Al多晶硅制成微加热器.使用ANSYS软件仿真加热器的工作过程,在10 V,0.3 μs脉冲驱动下,加热器升温至782.8 K,降温时间约1 μs.仿真分析显示,采用AIC法制得的掺Al多晶硅具有良好的热电特性,符合用于对高分子材料进行热机械微纳加工的微加热器的性能要求.%For thermomechanical fabrication of the micro/nano structure, a micro-heater made of A1 doped poly-Si was fabricated. The A1 doped poly-Si film was prepared by annealing from Al/a-Si ： H compound film under 750 K for 18 h on a Si3N4 substrate using Aluminium Induced Crystallization (AIC) process, and the characteristics of the transformation caused by annealing were analyzed by Raman scattering spectroscopy, scanning electron microscopy and a resistivity meter. It was shown that the boundary between an AI layer and an a-Si: H layer disappears after annealing,and a uniform film is formed. After annealing,the Raman spectral peak shifts from 478 em-1 to 520 cm-1 ,which means the film surface changes from the a-Si : H to the highly-crystallized poly-Si. Meanwhile, the resistivity of the film declined is from over 1010Ω ·cm to 16.8× 10-3 Ω ·cm at 300 K for doping of Al atoms.The results indicate that the bilayer film (Al/a-Si:H) has been changed into a uniform Al doped highly-crystallized ploy-Si film. Furthermore,the integration of the Al doped poly-Si micro-heater and Si3N4 cantilever was also discussed. Simulated by ANSYS, the micro-heater is heated to 782.8 K under a periodic electrical pulse with a voltage of 10 V and duration of 0.3 μs. When the pulse disappears, its temperature cools down to 420 K within 1 μs. The simulation results show that the Al doped poly-Si micro-heater has good thermoelectric properties, and it is well suitable for the thermomechanical micro/nano structure fabrication.