论文部分内容阅读
基于温度步进应力实验,研究了AlGaN/GaN HEMT器件在不同温度应力下的退化规律及退化机理。实验发现:在结温为139~200℃时,AlGaN/GaN HEMT器件的漏源电流随退化时间逐渐减小;而在结温为200~352℃时,漏源电流随退化时间逐渐增大。分析表明:结温低于200℃时,AlGaN施主原子的离化导致肖特基势垒高度升高;而在结温高于200℃时,表面氧杂质的扩散导致肖特基势垒高度逐渐降低。通过计算肖特基势垒高度,进一步定量的验证势垒高度的变化。而势垒高度的变化又引起阈值电压的漂移,进而影响漏源电流的变化。因此漏源电流的退化主要是由于势垒高度的变化引起的。
Based on the temperature step stress experiment, the degradation and degradation mechanisms of AlGaN / GaN HEMT devices under different temperature stress were studied. The experimental results show that the drain-source current of AlGaN / GaN HEMTs decreases with the degradation time at the junction temperature of 139 ~ 200 ℃, while the drain-source current gradually increases with the degradation time at the junction temperature of 200 ~ 352 ℃. The results show that when the junction temperature is lower than 200 ℃, the Schottky barrier height increases due to the dissociation of AlGaN donor atoms. When the junction temperature is higher than 200 ℃, the diffusion of surface oxygen impurities leads to the gradual increase of Schottky barrier height reduce. By calculating the Schottky barrier height, further quantitative verification of the barrier height change. The change of the barrier height also causes the threshold voltage drift, which in turn affects the drain-source current. Therefore, the degradation of the drain-source current is mainly caused by the change of the barrier height.