Direct Deposition of CVD Diamond Layers on Top of GaN Membranes

Tibor Izsák,Gabriel Vanko,Stephan Kasemann,Milan Držík,Johann Zehetner,Bohumír Zaťko,Marian Vojs,Alexander Kromka,Štěpán Potocký

doi:10.3390/proceedings2020056035

Abstract

We present technological issues in the deposition of diamond films on gallium nitride (GaN) membranes. Many wrinkles and thicker diamond layers were observed at the membrane center and poor quality diamond outside the membrane area. The deflection of the membranes was analyzed by a bulging method using white light interferometry. The membrane bending is discussed in the terms of temperature gradient and mismatch of thermal expansion coefficients of materials.

Highlights

Microelectromechanical systems (MEMS) and electronic devices based on gallium nitride (GaN) are prime candidates for sensor applications at high temperatures and in harsh environments
We studied back-side diamond deposition on GaN membranes
We show and discuss the technological issues related to front-side diamond deposition on GaN membranes, and we propose technological steps to overcome problems related to the recent procedure

Summary

Introduction

Microelectromechanical systems (MEMS) and electronic devices based on gallium nitride (GaN) are prime candidates for sensor applications at high temperatures and in harsh environments. We have already shown that a fully closed diamond layer on GaN membranes improves the performance of MEMS pressure sensors [1]. Diamond-coated GaN sensors better prevent the effect known as thermal buckling of the membrane at elevated temperatures.

Results

Conclusion