CMOS／SIMOX和CMOS／BESOI的γ射线辐照特性比较

用薄膜ＳＩＭＯＸ（ＳｅｐａｒａｔｉｏｎｂｙＩＭｐｌａｎｔａｔｉｏｎｏｆＯＸｙｇｅｎ）、厚膜ＢＥＳＯＩ（ｆｆｅｎｄｉｎｇａｎｄＥｔｃｈ－ｂａｃｋＳｉｌｉｃｏｎＯｎＩｎｓｕｌａｔｏｒ）和体硅材料制备了ＣＭＯＳ倒相器电路，并用６０Ｃｏγ射线进行了总剂量辐照试验。在不同偏置条件下，经不同剂量辐照后，分别测量了ＰＭＯＳ、ＮＭＯＳ的亚阈特性曲线，分析了引起ＭＯＳＦＥＴ阈值电压漂移的两种因素（辐照诱生氧化层电荷和新生界面态电荷）。对ＮＭＯＳ／ＳＩＭＯＸ，由于寄生背沟ＭＯＳ结构的影响，经辐照后背沟漏电很快增大，经３００Ｇｙ（Ｓｉ）辐照后器件已失效。而厚膜ＢＥＳＯＩ器件由于顶层硅膜较厚，基本上没有背沟效应，其辐照特性优于体硅器件。最后讨论了提高薄膜ＳＩＭＯＸ器件抗辐照性能的几种措施。

Comparison of γ-Ray Irradiation Characteristics of CMOS/SIMOX and CMOS/BESOI

The CMOS inverter circuits were fabricated on thin film SIMOX.(Separation by IMplantation of OXygen), thick film BESOI (Bonding and Etchback Silicon On Insulator) and bulk silicon materials. The effects of total dose irradiation with 60Co γ-ray on these circuits were studied. After irradiation with different bias conditions, the subthreshold characteristics of PMOS and NMOS were measured as a function of the accumulative dose, then two factors, radiation induced trapped oxide charge and new generated interface traps, causing threshold voltage shifts of the transistors were analyzed. For NMOS/SIMOX, due to the parasitic back-channel MOS structure, the leakage current increased quickly after irradiation, and the devices failed after 300 Gy(Si) irradiation.The thick BESOI devices did not have significant back-channel effects due to thicker top silicon layers.Their radiation characteristics were superior to that of the bulk silicon devices.Finally some methods to improve the radiation hardness of thin film SIMOX devices were discussed.