Effects of gate shaping and consequent process changes on AlGaN/GaN HEMT reliability
Effects of gate shaping and consequent process changes on AlGaN/GaN HEMT reliability
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DOI：
10.1002/pssa.201228395
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发表时间：
2012-12
期刊：
影响因子：
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通讯作者：
J. Möreke;M. Ťapajna;M. Uren;Y. Pei;U. Mishra;M. Kuball
中科院分区：
文献类型：
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作者：
J. Möreke;M. Ťapajna;M. Uren;Y. Pei;U. Mishra;M. Kuball
采用直流和脉冲HEMT分析方法，研究了栅形状及其必要的制作工艺对AlGaN/GaN高电子迁移率晶体管（HEMT）可靠性的影响。模拟用于确定所研究的三种栅极形状（I形、倾斜和凹进倾斜）的表面上和势垒中的电场差异。在强制降解期间进行每次电气表征之前，将器械暴露于紫外线照射，以仅探测新生成的陷阱，而不是填充预先存在的电子陷阱。退化被认为是增加与电场强度，在每种设备类型的陷阱产生的设备应力的峰值电场的位置。结果发现，在相同的应力条件下，具有I形栅极的HEMT比具有倾斜栅极的器件表现出更大的退化。这是由于SiNx钝化层和AlGaN势垒层之间的界面处的较高电场导致较高的表面陷阱产生。具有倾斜凹陷栅极的HEMT显示出势垒俘获的迹象，而表面俘获效应起较小的作用。
The effect of gate shape and its necessary fabrication process on the reliability of AlGaN/GaN high electron mobility transistors (HEMT) was studied on devices fabricated on the same wafer, using DC and pulsed HEMT analysis. Simulations were used to determine the difference in electric field on the surface and in the barrier for the three gate shapes studied, I‐shaped, slanted, and recessed slanted. Prior to each electrical characterization during stress, devices were exposed to ultraviolet illumination to probe only newly generated traps rather than the filling of pre‐existing electronic traps. Degradation was seen to increase with electric field strength; in each device type traps were generated by device stress at the location of the peak electric field. It was found that HEMTs with I‐shaped gates showed larger degradation under the same stress conditions than devices with slanted gates. This was due to a higher electric field at the interface between the SiNx passivation and the AlGaN barrier layer resulting in higher surface trap generation. HEMTs with slanted recessed gates showed indications of barrier trapping while surface trapping effects played a smaller role.