高温应力下SiO_(2)/SiC近界面碳缺陷的结构与电子特性演变  

Evolution of Structure and Electronic Properties of Carbon Defects Near SiO_(2)/SiC Interface Under High Temperature Stress

作　　者：丁攀 尉升升 张圆 白娇 苏艳 王德君 Ding Pan;Wei Shengsheng;Zhang Yuan;Bai Jiao;Su Yan;Wang Dejun(School of Control Science and Engineering,Faculty of Electronic Information and Electrical Engineering,Dalian University of Technology,Dalian 116024,China;School of Physics,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学电子信息与电气工程学部控制科学与工程学院,辽宁大连116024 [2]大连理工大学物理学院,辽宁大连116024

出　　处：《半导体技术》2023年第7期557-562,576,共7页Semiconductor Technology

基　　金：国家自然科学基金资助项目(61874017)。

摘　　要：SiO_(2)/SiC近界面碳缺陷是引起高温应力下SiC MOSFET可靠性劣化的主要根源。采用第一性原理密度泛函理论结合分子动力学,模拟计算了高温应力(425~625 K,间隔100 K)对SiO_(2)/SiC近界面碳缺陷(如羧基类、碳二聚体、碳三聚体等缺陷)结构和电子特性的影响。计算结果表明:施加高温应力后,羧基类碳缺陷结构稳定;碳二聚体缺陷的碳碳双键(C═C)转变为碳碳单键(C—C),且无法在SiC带隙中引入电荷态;碳三聚体缺陷在施加高温应力后转变为新的C═C和碳氧双键(C═O)复合缺陷。这种复合缺陷在SiC的价带顶和导带底附近均引入了缺陷态,有较强的电子捕获能力,是SiC MOSFET在高温应力下性能不稳定的主要因素。The carbon defects near the SiO_(2)/SiC interface are main causes of reliability degradation of SiC MOSFETs under high temperature stress.The effects of high temperature stresses(425-625 K,10o K interval)on the structures and electronic properties of carbon defects(such as carboxyl group,carbon dimer,carbon trimer,etc.)near the SiO_(2)/SiC interface were simulated by using first-principles density functional theory combined with molecular dynamics.The calculation results show that the carboxyl carbon defect structure is stable after the application of high temperature stress;the C-C bond of the carbon dimer defect is transformed into a C-C bond,and the charge state can not be introduced into the SiC band gap;the carbon trimer defect is transformed into a new defect compound by C-C and C-O after the application of high temperature stress.The compound defect introduces defect states near the top of the SiC valence band and the bottom of the SiC conduction band,and has a strong electron capture ability,which is the main factor for the unstable performance of the SiC MOSFET under high temperature stress.

关 键 词：碳化硅(SiC) 界面碳缺陷 高温应力 电子结构 电子捕获 

分 类 号：TN386.1[电子电信—物理电子学]