Effects of recess process and surface treatment on the threshold voltage of GaN MOSFETs fabricated on a AlGaN/GaN heterostructure
Effects of recess process and surface treatment on the threshold voltage of GaN MOSFETs fabricated on a AlGaN/GaN heterostructure
复制标题
DOI：
10.1088/0268-1242/30/6/065004
复制
发表时间：
2015-05
影响因子：
1.9
通讯作者：
Qingpeng Wang;Ying Jiang;Jiaqi Zhang;K. Kawaharada;Liuan Li;Dejun Wang;J. Ao
中科院分区：
文献类型：
--
作者：
Qingpeng Wang;Ying Jiang;Jiaqi Zhang;K. Kawaharada;Liuan Li;Dejun Wang;J. Ao
在具有凹栅的 AlGaN/GaN 异质结构上制造了 GaN MOSFET。评估了不同蚀刻条件下 GaN MOSFET 的 SiO2/GaN 界面附近的电荷。研究发现，干法过程中更强的轰击损伤会在界面附近带来更多的电荷，最终使器件的阈值电压为负值。研究了氮等离子体处理和氨水（NH4OH）处理来恢复或去除受损层，以便在干凹半绝缘（SI）GaN表面上实现具有正阈值电压的增强模式（E模式）器件。这些处理对界面态密度的影响也通过使用 GaN MOS 电容器使用 Terman 方法进行了表征。通过NH4OH处理，实现了最大场效应迁移率148.1 cm2 V−1 s−1的E型GaN MOSFET和界面态密度为3×1011 cm−2 eV−1的MOS电容器。
GaN MOSFETs on a AlGaN/GaN heterostructure with a recess gate were fabricated. The charges near the SiO2/GaN interface of the GaN MOSFETs with different etching conditions were evaluated. It was found that stronger bombardment damage in the dry process will bring more charges near the interface and finally make the threshold voltage of the device negative. Nitrogen plasma treatment and ammonia water (NH4OH) treatment were investigated to recover or remove the damaged layer in order to achieve an enhancement-mode (E-mode) device with positive threshold voltage on the dry-recessed semi-insulating (SI) GaN surface. The influence of these treatments on the interface state density was also characterized using the Terman method by using the GaN MOS capacitor. An E-mode GaN MOSFET with a maximum field-effect mobility of 148.1 cm2 V−1 s−1 and a MOS capacitor with an interface state density of 3 × 1011 cm−2 eV−1 were realized by the NH4OH treatment.