Investigation of current transport parameters of Ti/4H-SiC MPS diode with inhomogeneous barrier

• Published in: Chinese physics B Vol. 20; no. 5; pp. 353 - 358
• Main Author: 宋庆文 张玉明 张义门 陈丰平 汤晓燕
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.05.2011
• Subjects: MPS结构; PIN二极管; 不均匀; 传输参数; 屏障; 温度范围; 电流; 肖特基势垒
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/5/057301

The current transport parameters of 4H-SiC merged PiN Schottky （MPS） diode are investigated in a temperature range of 300-520 K. Evaluation of the experimental current-voltage （I-V） data reveals the decrease in Schottky barrier height Φb but an increase in ideality factor n, with temperature decreasing, which suggests the presence of an inhomogeneous Schottky barrier. The current transport behaviours are analysed in detail using the Tung＇s model and the effective area of the low barrier patches is extracted. It is found that small low barrier patches, making only 4.3% of the total contact, may significantly influence the device electrical characteristics due to the fact that a barrier height of 0.968 eV is much lower than the average barrier height 1.39 eV. This shows that ion implantation in the Schottky contact region of MPS structure may result in a poor Ti/4H-SiC interface quality. In addition, the temperature dependence of the specific on-resistance （Ron-sp）, T^2.14, is determined between 300 K and 520 K, which is similar to that predicted by a reduction in electron mobility.