SOI MOSFET浮体效应与抑制的研究

Physical Model of Floating Body Effects and Its Suppression Study in Fully Depleted SOI MOSFETs

提出了一个新的物理解析模型分析薄膜ＳＯＩＭＯＳＦＥＴ强反型电流下的浮体效应，该模型考虑了器件的各种寄生电流成分，着重研究了浮体电位及其对其他器件参数和各寄生电流成分的影响，成功地解释了器件处于背界面积累状态时的Ｋｉｎｋ现象和器件的异常击穿机理。根据所建浮体效应物理模型，研究了器件参数对ＳＯＩＭＯＳＦＥＴ浮体效应影响关系。结果表明，降低源漏掺杂浓度、减小体区少子寿命、采用优化的硅膜厚度、以及在保持器件全耗尽情形下适当提高沟道掺杂浓度，可以有效地抑制浮体效应，提高器件的源漏击穿电压。这些参数在工艺上可以对应采用ＬＤＤ＆ＬＤＳ的ＭＯＳ结构、准确控制的沟道缺陷工程等，为从工艺设计上进一步改善ＳＯＩＭＯＳＦＥＴ的器件特性打下了理论基础。

A new analytical model for SOI MOSFET with floating body effect(FBE) is developed to described the SOI MOSFET’s strong inversion current characteristics.Considering all current components,the model can explain the physical mechanism of the current kink and breakdown phenomena as well as the dependence of I V characteristics on various bias and channel length successfully.Based on this model,the dependence of FBE on several device parameters is studied.The results show that lowing source/drain doping、decreasing minority carrier life time、optimizing the silicon film thickness and reducing channel doping will effectively suppress the FBE with much improved breakdown voltage characteristics.The experiments corresponding to the suppression of FBE with LDD&LDS structure and channel defect engineering, etc.,demonstrate the calculated analysis,thereby enabling the theoretical result’s realization in CMOS/SOI technology.