High-Frequency AlGaN/GaN High-Electron-Mobility Transistors with Regrown Ohmic Contacts by Metal-Organic Chemical Vapor Deposition

Abstract

Nonalloyed ohmic contacts regrown by metal-organic chemical vapor deposition are performed on AlGaN/GaN high-electron-mobility transistors. Low ohmic contact resistance of 0.15 Ω•mm is obtained. It is found that the sidewall obliquity near the regrown interface induced by the plasma dry etching has great influence on the total contact resistance. The fabricated device with a 100-nm T-shaped gate demonstrates a maximum drain current density of 0.95 A/mm at 𝑉gs = 1 V and a maximum peak extrinsic transcondutance 𝐺m of 216 mS/mm. Moreover, a current gain cut-off frequency 𝑓T of 115 GHz and a maximum oscillation frequency 𝑓max of 127 GHz are achieved.

Low-resistance ohmic contacts on InAlN/GaN heterostructures with MOCVD-regrown n+-InGaN and mask-free regrowth process

“…[15][16][17] Low contact resistance of 0.16 Ω•mm in AlGaN/GaN structure has also been achieved with heavily doped material regrown by metal-organic chemical vapor deposition (MOCVD), which has the advantages of production capacity and cost. [18][19][20] However, few reports have involved in the regrown ohmic contacts of InAlN/GaN using MOCVD, because the high temperature regrowth process will cause another challenge on the degradation of InAlN.…”

Removal of GaN film over AlGaN with inductively coupled BCl3/Ar atomic layer etch

“…AlGaN is widely used to construct AlGaN/GaN heterostructures to generate high-density two-dimensional electron gas (2DEG) for the applications in power electronics. [1][2][3][4][5][6][7] AlGaN is also used as a wide band gap electron barrier in light-emitting diodes and laser diodes. [4,8] In device manufacturing, it is difficult to achieve the uniform and precise height of the design pattern through conventional etching methods.…”

“…[1][2][3][4][5][6][7] AlGaN is also used as a wide band gap electron barrier in light-emitting diodes and laser diodes. [4,8] In device manufacturing, it is difficult to achieve the uniform and precise height of the design pattern through conventional etching methods. [9] At the same time, it is usually necessary to keep the AlGaN (or AlN) layer in place.…”

Comparison of resonant tunneling diodes grown on freestanding GaN substrates and sapphire substrates by plasma-assisted molecular-beam epitaxy*

“…III-nitride semiconductor materials are suitable for high frequency and power devices because of their excellent properties such as wide bandgap energy, high breakdown fields, high peak electron velocity, high saturated electron velocity, and strong thermal stability. [5,6] Therefore, GaNbased RTDs have attracted more attention in the research field of terahertz sources. [7][8][9][10][11][12][13][14][15][16][17] Many research groups have achieved stable reproducible negative differential resistance (NDR) utilizing RTDs at room temperature.…”