A Novel GaN:C Millimeter-Wave HEMT with AlGaN Electron-Blocking Layer.

You-Chen Weng,Chang-Fu Dee,Heng-Tung Hsu,Jer-Shen Maa,Min-Lu Kao,Yueh-Chin Lin,Daisuke Ueda,Edward-Yi Chang,Minh-Thien-Huu Ha,Hsuan-Yao Huang,Chih-Yi Yang

doi:10.3390/ma15030703

Abstract

An AlGaN/GaN/Si high electron mobility transistor (HEMT) using a GaN:C buffer with a 2 nm AlGaN electron-blocking layer (EBL) is investigated for the first time for millimeter-wave applications. Compared with the double heterostructure field effect transistor (DHFET), the AlGaN/GaN HEMT with the GaN:C/EBL buffer has a lower vertical leakage, higher thermal stability, and better RF performance. In addition, AlGaN EBL can prevent carbon-related traps from GaN:C and improve electron confinement in 2DEG during high-frequency operation. Finally, a Pout of 31.2 dBm with PAE of 21.7% were measured at 28 GHz at 28 V. These results demonstrated the great potential of HEMTs using GaN:C with AlGaN EBL epitaxy technology for millimeter-wave applications.

Highlights

Academic Editor: Albert GuijarroDue to the wide bandgap and high mobility nature of the GaN material, AlGaN/GaNhigh electron mobility transistor (HEMT) have become one of the most popular devices for high-frequency and high-power applications, including 5G applications, in recent years
RF loss caused by the buffer layers for AlGaN/GaN HEMTs on Si substrate results in a lower output power when the device is used for millimeter-wave applications
C and a thin layer of (Al) atoms were observed at a distance of 500 nm below the surface, showing evidence that an amount of Al atoms existed between the GaN:C and unintentionally doped (UID) GaN channel

Summary

Introduction

Academic Editor: Albert GuijarroDue to the wide bandgap and high mobility nature of the GaN material, AlGaN/GaNHEMTs have become one of the most popular devices for high-frequency and high-power applications, including 5G applications, in recent years. The fabrication cost of AlGaN/GaN HEMTs on SiC is very high. AlGaN/GaN HEMTs on Si substrate for Ka band applications have become popular [5], since GaN-on-Si substrate technology has the benefit of fabricating devices on large wafers (up to 8 inch) with silicon-compatible processes [6,7] to reduce manufacturing costs as compared with GaN-on-SiC technology. RF loss caused by the buffer layers for AlGaN/GaN HEMTs on Si substrate results in a lower output power when the device is used for millimeter-wave applications. A buffer was grown to balance the lattice and thermal mismatch between GaN and Si for stress control, three major types of buffer structures have been studied in the past [9], namely, the step AlGaN buffer, the Received: 28 November 2021

Methods

Results

Conclusion