GaN-on-diamond technology platform: Bonding-free membrane manufacturing process

Matthew D Smith,Martin Kuball,Yen-Chun Fu,Michael J Uren,Soumen Mandal,Oliver A Williams,Chao Yuan,Iain Thayne,James W Pomeroy,Jerome A Cuenca,Daniel E Field,Fabien Massabuau,Khaled Elgaid,Rachel A Oliver

doi:10.1063/1.5129229

Abstract

GaN-on-diamond samples were demonstrated using a membrane-based technology. This was achieved by selective area Si substrate removal of areas of up to 1 cm × 1 cm from a GaN-on-Si wafer, followed by direct growth of a polycrystalline diamond using microwave plasma chemical vapor deposition on etch exposed N-polar AlN epitaxial nucleation layers. Atomic force microscopy and transmission electron microscopy were used to confirm the formation of high quality, void-free AlN/diamond interfaces. The bond between the III-nitride layers and the diamond was validated by strain measurements of the GaN buffer layer. Demonstration of this technology platform is an important step forward for the creation of next generation high power electronic devices.

Highlights

Transistors created on a GaN-on-diamond material system have attracted significant interest in recent years due to their increased high frequency and high power handling potential when compared to commercially established GaN-on-SiC technologies
A polycrystalline diamond is deposited directly on membranes formed from GaN-on-Si wafers by selective area substrate removal, enabling the growth of a 50 μm thick crack-free diamond directly on the exposed back-side (N-polar face) of AlN epitaxial nucleation layers
AlGaN/GaN heterostructures were grown by metalorganic chemical vapor deposition on 1 mm thick Si substrates of a diameter of 150 mm

Summary

Introduction

Transistors created on a GaN-on-diamond material system have attracted significant interest in recent years due to their increased high frequency and high power handling potential when compared to commercially established GaN-on-SiC technologies. A polycrystalline diamond is deposited directly on membranes formed from GaN-on-Si wafers by selective area substrate removal, enabling the growth of a 50 μm thick crack-free diamond directly on the exposed back-side (N-polar face) of AlN epitaxial nucleation layers.

Results

Conclusion