C-V法提取SiC隐埋沟道MOSFET沟道载流子浓度

Extraction of channel carrier concentration using C-V method for SiC buried-channel MOSFET

本文对用C-V法提取SiC隐埋沟道MOSFET沟道载流子浓度的方法进行了理论和实验分析.pn结的存在所造成的埋沟MOS结构C-V曲线的畸变为沟道载流子浓度的提取带来一些问题.SiC/SiO2界面上界面态的存在也会使提取出的数值与实际数值产生偏差.本文首先从理论上分别分析了沟道深度和界面态对沟道载流子浓度提取结果的影响,然后对两种沟道深度的埋沟MOS结构C-V曲线进行了测试,提取出了沟道掺杂浓度.在测试中,采用不同的扫描速率,分析了界面态对提取结果的影响.理论分析结果和实验测试结果相一致.

A theoretical and experimental study on extracting channel carrier concentration for 4H-SiC buried channel MOSFET has been carried out. The distortion of C-V curve caused by the existence of p-n junction in buried channel MOS structure would affect the extracting result, and the interface states on SiO2/SiCinterface make extracting result deviate from true channel carrier concentration. In this paper, firstly, a theoretical analysis about the effects of channel depth and interface state on extracting result is made. Then the C-V curves for buried-channel MOS structure with two different channel depth are presented from which the channel carder concentration is extracted. In the measurement of C-V curves, three different sweep velocities are used to analyze the effect of interface states. The theoretical results agree with experimental results.