Silicon Accelerometer for high temperature applications with Double SOI structure

本研究采用SOI结构和微机械加工技术，研制了一种高温加速度计。首先，利用超高真空化学气相沉积(UHV-CVD)和热壁加热系统生长了双SOI结构[Si/Al203/Si]。生长在Si(100)衬底上的Al203(100)外延薄膜可用作SOI器件的刻蚀阻止层和电隔离层。开发了SOI器件的另一项重要技术：一种是利用硅离子注入方法对化学稳定的A1203薄膜和蓝宝石晶片进行刻蚀的新方法；另一种是利用电子束辐照方法在Al203(100)上选择性外延生长Si(100)以形成精细图形的方法。在此基础上，利用ANSYS有限元软件设计了一种新型压阻式硅加速度计和一种电容式加速度计，并采用微机械加工技术和集成电路技术对其进行了加工。该加速度计可以检测三维加速度。其次，研制了一套高达400ﾟC的高温测试系统，并对加速度计的性能进行了评估。该加速度计在高达400ﾟC的温度下稳定工作，证实了SOI结构极大地改善了其高温特性。并将其温度特性和输出特性与模拟结果进行了比较，两者吻合较好。

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.