中国物理B ›› 2009, Vol. 18 ›› Issue (1): 315-319.doi: 10.1088/1674-1056/18/1/051

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A new analytical model of high voltage silicon on insulator (SOI) thin film devices

胡盛东, 张波, 李肇基   

  1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
  • 收稿日期:2008-05-20 修回日期:2008-08-29 出版日期:2009-01-20 发布日期:2009-01-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 60436030) and National Laboratory of Analogue Integrated Circuits, China (Grant No 9140C090305060C09).

A new analytical model of high voltage silicon on insulator (SOI) thin film devices

Hu Sheng-Dong(胡盛东)†, Zhang Bo(张波), and Li Zhao-Ji(李肇基)   

  1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
  • Received:2008-05-20 Revised:2008-08-29 Online:2009-01-20 Published:2009-01-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 60436030) and National Laboratory of Analogue Integrated Circuits, China (Grant No 9140C090305060C09).

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摘要： A new analytical model of high voltage silicon on insulator (SOI) thin film devices is proposed, and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate, with a threshold energy taken into account for electron multiplying. Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness, the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films, and can come to 141V/μm at a film thickness of 0.1μm which is much larger than the normal value of about 30V/μm. From the proposed formula of silicon critical electric field, the expressions of dielectric layer electric field and vertical breakdown voltage (VB,V) are obtained. Based on the model, an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field, and with a dielectric layer thickness of 2μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5μm, respectively. In addition, a relation between dielectric layer thickness and silicon film thickness is obtained, indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed. 2D simulated results and some experimental results are in good agreement with analytical results.

关键词: silicon critical electric field, breakdown voltage, thin silicon layer, SOI high voltage device

Abstract: A new analytical model of high voltage silicon on insulator (SOI) thin film devices is proposed, and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate, with a threshold energy taken into account for electron multiplying. Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness, the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films, and can come to 141V/μm at a film thickness of 0.1μm which is much larger than the normal value of about 30V/μm. From the proposed formula of silicon critical electric field, the expressions of dielectric layer electric field and vertical breakdown voltage (VB,V) are obtained. Based on the model, an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field, and with a dielectric layer thickness of 2μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5μm, respectively. In addition, a relation between dielectric layer thickness and silicon film thickness is obtained, indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed. 2D simulated results and some experimental results are in good agreement with analytical results.

Key words: silicon critical electric field, breakdown voltage, thin silicon layer, SOI high voltage device

中图分类号:  (Semiconductor devices)

  • 85.30.-z
68.55.-a (Thin film structure and morphology) 73.40.Qv (Metal-insulator-semiconductor structures (including semiconductor-to-insulator))