Electric Field Engineering in Graded-Channel GaN-Based HEMTs
Electric Field Engineering in Graded-Channel GaN-Based HEMTs
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分级沟道 GaN 基 HEMT 中的电场工程
DOI：
10.1109/bcicts50416.2021.9682456
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
P. Fay
中科院分区：
文献类型：
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作者：
N. Venkatesan;J. Moon;P. Fay
基于AlGaN/GaN的高电子迁移率晶体管（HEMT）是从RF到毫米波的高功率和低噪声应用的优秀候选者。然而，传统器件设计中的输出功率缩放已被证明具有挑战性，特别是在高频下。作为一种设计替代方案，渐变沟道HEMT由于设计灵活性而显示出改善的DC和RF性能，该设计灵活性使得能够在保持高速的同时定制介电常数（gm）和器件电容。在实验上，与传统HEMT相比，渐变沟道器件还表现出在不需要场板的情况下改进的输出功率缩放，以及在低电流密度下的更高速度和更低噪声。为了理解这些结果，我们报告了一个详细的研究梯度沟道HEMT。我们发现，使用一个梯度沟道结构，使工程不仅电荷分布（控制gm和电容），但也横向电场分布。与传统上使用场板来最小化栅极-漏极区中的表面电场的突变AlGaN/GaN HEMT相比，渐变沟道HEMT可以通过沟道工程实现显著减小的电场。这使得它们有希望用于高性能毫米波应用。
AlGaN/GaN based high electron mobility transistors (HEMTs) are excellent candidates for high power and low-noise applications from RF through the millimeter wave. However, output power scaling in conventional device designs has proven challenging, especially at high frequencies. As a design alternative, graded-channel HEMTs have shown improved DC and RF performance due to the design flexibility that enables tailoring the transconductance (gm) and device capacitances, while maintaining high speed. Experimentally, graded-channel devices have also demonstrated improved output power scaling without the need for field plates, as well as higher speed and lower noise at low current densities, compared to conventional HEMTs. To understand these results, we report a detailed study of graded-channel HEMTs. We find that the use of a graded-channel structure enables engineering of not only the charge distribution (which controls the gm and capacitances) but also the lateral electric field profile. In contrast to abrupt AlGaN/GaN HEMTs which traditionally use field plates to minimize the surface electric fields in the gate-drain region, graded channel HEMTs can achieve significantly reduced electric fields through channel engineering. This makes them promising for high performance millimeter-wave applications.