Improvement of GaN Deep Etched Surface State by Fluorination Dedicated to Power Devices

Abstract

In this paper, the etched surface states of GaN using two different etching techniques are reported. In Cl2/Ar ICP based plasma, two types of defect were identified: cavities and columns. A strong decrease of the cavity diameter and density on etched surface was observed with the addition of CHF3 in the chemistry. SF6 addition instead of CHF3 leads to an etched surface free of defects with low GaN etch rate similar to that obtained with IBE technique. XPS and AFM measurements revealed the importance of fluorine species which leads to the formation of a GaxFy passivation layer on the GaN etched surface.