Gate-geometry dependence of electrical characteristics of p-GaN gate HEMTs
Author(s)
Lee, Ethan S; Joh, Jungwoo; Lee, Dong Seup; del Alamo, Jesús A
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<jats:p> In this Letter, we experimentally investigate the impact of gate geometry on forward operation of Schottky-gate p-GaN high electron mobility transistors (HEMTs). In particular, we analyze devices with changing gate-metal/p-GaN junction area and p-GaN/AlGaN/GaN heterostructure area in the linear regime. These devices exhibit unique threshold voltage and subthreshold swing scaling dependence with gate geometry that is in contrast with classic field-effect transistors. On the other hand, peak transconductance and ON resistance are found to scale classically. We find that these results arise from the fact that with a Schottky contact to the p-GaN layer, under steady-state conditions, the p-GaN layer voltage is set by current continuity across the gate stack. Furthermore, a detailed scaling study of the gate current reveals that current flow across the p-GaN/AlGaN/GaN heterostructure is not uniform—instead, it preferentially flows through the ungated portion of the p-GaN layer. Our study concludes that in Schottky-type p-GaN gate HEMTs, the respective areas of two junctions constitute an additional design degree of freedom to fine-tune device performance. </jats:p>
Date issued
2022Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science; Massachusetts Institute of Technology. Microsystems Technology LaboratoriesJournal
Applied Physics Letters
Publisher
AIP Publishing
Citation
Lee, Ethan S, Joh, Jungwoo, Lee, Dong Seup and del Alamo, Jesús A. 2022. "Gate-geometry dependence of electrical characteristics of p-GaN gate HEMTs." Applied Physics Letters, 120 (8).
Version: Final published version