Al2O3绝缘栅SiC MIS结构基本特性的研究  

Fundamental characteristics of SiC MIS structure with Al_2O_3 as gate dielectric

作　　者：刘莉[1] 杨银堂[1] 马晓华[2] 

机构地区：[1]西安电子科技大学微电子学院,教育部宽禁带半导体材料与器件重点实验室,西安710071 [2]西安电子科技大学技术物理学院,西安710071

出　　处：《科学通报》2011年第11期822-827,共6页Chinese Science Bulletin

基　　金：西安电子科技大学2010年校内基本科研业务费资助项目(K50510250008)

摘　　要：采用原子层淀积（ALD）方法在4H-SiC（0001）8°N-/N＋外延层上制备了超薄（~4nm）Al2O3绝缘栅高介电常数SiCMIS电容.通过对Al2O3介质膜以及Al2O3/SiC界面微结构和电学特性分析表明,实验所得Al2O3介质膜具有较好的体特性和界面特性,Al2O3薄膜的击穿电场为25MV/cm,并且在可以接受的界面态密度（2×1013cm-2）下具有较小的栅泄漏电流（8MV/cm电场下漏电流密度为1×10-3A/cm-2）.电流-电压测试分析表明,在FN隧穿条件下,SiC/Al2O3之间的势垒高度为1.4eV,已达到制作SiCMISFET器件的要求.同时,在整个栅压区域也受Frenkel-Poole和Schottky机制的共同影响.SiC MIS structure with ultra-thin Al2O3 as gate dielectric deposited by atomic layer deposition （ALD） on epitaxial layer of 4H-SiC（0001）8°N？/N＋ substrate is fabricated. The microstructure and electrical characteristics analysis on the film and Al2O3/SiC interface has shown that Al2O3 deposited has a good bulk characteristics and a good quality between Al2O3 and SiC. The breakdown electrical field of Al2O3 film is 25 MV/cm; the MIS capacitor has a fairly low gate leakage current （current density of 1×10？3A/cm？2 with a electric field of 8 MV/cm） under acceptable interface effective charge （2×1013 cm？2）. Current-voltage measurement and analysis has shown that when the gate leakage current mechanism is dominated by FN tunneling, the barrier height of SiC/Al2O3 is 1.4 eV, which can meet the requirement of SiC MISFET devices. Besides this, the gate leakage current is co-influenced by both of Frenkel-Poole mechanism and Schottky emission.

关 键 词：AL2O3 SIC MIS电容 栅泄漏电流 C-V特性 

分 类 号：O484.1[理学—固体物理]