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论文类型：期刊论文

发表时间：2011-09-15

发表刊物：APPLIED SURFACE SCIENCE

收录刊物：Scopus、SCIE、EI

卷号：257

期号：23

页面范围：10172-10176

ISSN号：0169-4332

关键字：4H-SiC; Surface cleaning; Electronic cyclotron resonance hydrogen plasma; Reflection high energy electron diffraction; X-ray photoelectron spectroscopy

摘要：N-type 4H-SiC (0 0 0 1) surfaces were cleaned by low temperature hydrogen plasma in electronic cyclotron resonance (ECR) microware plasma system. The effects of the hydrogen plasma treatment (HPT) on the structure, chemical and electronic properties of surfaces were characterized by in situ reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). The RHEED results indicate that the structures of the films are strongly dependent on the treatment temperature and time. Significant improvements in quality of 4H-SiC films can be obtained with the temperature ranging from 200 degrees C to 700 degrees C for an appropriate treatment period. The XPS results show that the surface oxygen is greatly reduced and the carbon contamination is completely removed from the 4H-SiC surfaces. The hydrogenated SiC surfaces exhibit an unprecedented stability against oxidation in the air. The surface Fermi level moves toward the conduction band in 4H-SiC after the treatment indicating an unpinning Fermi level with the density of surfaces states as low as 8.09 x 10(10) cm(-2) eV(-1). (C) 2011 Elsevier B.V. All rights reserved.