Silicon Accelerometer for high temperature applications with Double SOI structure

在本研究中，利用SOI结构和微加工技术开发了一种适用于高温的加速度计。首先，采用热壁加热的超高真空化学气相沉积（UHV-CVD）法制备了双SOI结构[Si/Al203/Si]。在Si（100）衬底上生长的外延Al203（100）薄膜可以用作SOI器件的刻蚀停止层和电隔离层。开发了SOI器件的另一项重要技术：一是采用硅离子注入法刻蚀化学稳定的A1203薄膜和蓝宝石晶片，二是采用电子束辐照法在Al203（100）上选择性外延生长Si（100）以制备精细图案。因此，双SOI结构的基本技术已经开发用于高温加速度计。然后，采用ANSYS有限元法设计了一种新型压阻式硅加速度计和电容式加速度计。这些加速度计采用微加工技术和集成电路技术制作。加速度计可以检测三维加速度。然后，开发了一个高达400ºC的高温加速度计封装和测量系统，并对加速度计的特性进行了评估。该加速度计在高达400℃的温度下稳定工作，证明了SOI结构大大改善了加速度计的高温特性。将温度特性和输出特性与仿真结果进行了比较，结果与仿真结果吻合较好。

In this study, an accelerometers for high temperature application have been developed using SOI structure and micromachining technology. At first, an ultrahigh-vacuum chemical vapor deposition (UHV-CVD) with a hot wall heating system have developed to grow double SOI structure [Si/Al203/Si]. The epitaxial Al203 (100) film grown on a Si (100) substrate can be used as etching stop layr and as an electric-isolation layr of an SOI device. Another important technologies for the SOI devices were developed : the one is a new etching method of chemically stable A1203 films and sapphire wafers by Si ion implantation method, and the another is the selective epitaxial growth of Si (100) on Al203 (100) by electron-beam-irradiation method to make fine pattern. As the result, the fundamental technologies for double SOI structure has been developed for accelerometers for high temperature applications.Then, a novel piezoresistive silicon accelerometer and a capacitive accelerometer were designed with finite element method (FEM) of ANSYS.These acoelerometers were fabricated with micromachining technology and integrated circuit technology. The accelerometers can be detect three dimensional acceleration. Next, a package and a measurement system for high temperature up to 400ﾟC were developed, and the characteristics of accelerometers were evaluated. The accelerometer successfully worked at up to 400ﾟC stably, so that it was confirmed that the SOI structure greatly improve the characteristics at high temperature. The temperature characteristics and the output characteristics were compared with simulated result, and it well agrees with simulated result.