The forward and reverse I-V characteristics of Anode-Gate diodes passivated with pyrogenic and dry oxide in 4H-SiC gate turn-off thyristor (GTO) were investigated by device size dependent measurement. The bulk and surface current component were manifested and separated, where the surface recombination velocity was accurately evaluated as 10$^5$−10$^6$ cm/s. Pyrogenic oxide was found more effective than dry oxide to suppress surface traps induced excess carrier recombination and carrier generation at etched p $^+$ n mesa sidewall. Moreover, temperature dependent measurement revealed that excess current of Anode-Gate diodes is primarily attributed to carrier recombination and generation from surface traps. Surface traps dominates the reverse leakage below 125 $^{\circ }$C, while electrically active bulk defects contributes to the reverse leakage simultaneously at elevated temperature. Finally, the influence of passivation on the 4H-SiC GTOs forward characteristics was demonstrated. Higher gate trigger current needed to switch from blocking to conduction state for the 4H-SiC GTOs with dry oxide passivated Anode-Gate mesa sidewall.

中文翻译：

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4H-SiC栅极关断晶闸管中Anode-Gate台面侧壁的表面复合和过电流

前进和后退 四通过器件尺寸相关测量研究了在 4H-SiC 栅极关断晶闸管 (GTO) 中用热解和干氧化物钝化的阳极-栅极二极管的特性。体积和表面电流分量被显现和分离，其中表面复合速度被准确评估为 10$^5$−10$^6$厘米/秒。发现热解氧化物比干氧化物更有效地抑制表面陷阱诱导的过量载流子复合和蚀刻 p 处的载流子生成$^+$n 台面侧壁。此外，温度相关测量表明，阳极-栅极二极管的过电流主要归因于载流子复合和表面陷阱的产生。表面陷阱在 125 以下的反向泄漏中占主导地位$^{\circ }$C，而电活性体缺陷在升高的温度下同时导致反向泄漏。最后，证明了钝化对 4H-SiC GTO 正向特性的影响。对于具有干氧化物钝化阳极-栅极台面侧壁的 4H-SiC GTO，从阻塞状态切换到导通状态需要更高的栅极触发电流。