改善GaAs MESFETs硫钝化稳定性研究的新探索

An New Research in Improving the Sulfur Passivation Stability of GaAs MESFETs

硫钝化可以明显改善GaAs金属半导体场效应晶体管(MESFETs)的击穿特性,但钝化效果不稳定。我们利用硫钝化和PECVD SiNx 钝化相结合的方法,使钝化的稳定性得到了提高,但同时击穿电压会出现下降。击穿电压下降的主要原因是:As S键很不稳定,在较高温度下分解,使GaAs表面负电荷密度减小,击穿电压下降。

The breakdown characteristic of GaAs metal-semiconductor field effect transistors (MESFETs) can be greatly improved by sulfur passivation technique. However, the passivation effect is unstable. A novel method combining sulfur passivation with PECVD SiN_x passivation is developed. The experiment results indicate that a stable passivation effect can be achieved by this passivation technique, but the breakdown voltage decreased simultaneously. Breaking down of As-S bond in high temperature reduced the density of negative charge, which is the main reason that the breakdown voltage decreased.