The insertion of the ALD diffusion barriers: An approach to improve the quality of the GaN deposited on Kapton by PEALD

Abstract

The influence of growth temperature (200–300 ℃) on the properties of gallium nitride (GaN) directly deposited on Kapton by plasma-enhanced atomic layer deposition (PEALD) has been systematically investigated. With increasing growth temperatures, the O content and surface roughness of the GaN thin films increase. Besides, the diffusion behavior of GaN in Kapton was found when the growth temperature exceeds 250 ℃. In this study, ultrathin ALD aluminum oxide (Al2O3) and aluminum nitride (AlN) films were proposed to see if they could alleviate and/or even suppress the negative effects of interface diffusion during high-temperature (≥250 ℃) GaN growth. It was found that oxygen impurities were significantly decreased within the as-deposited GaN. Furthermore, we observed a complete suppression of GaN diffusion into the Kapton throughout the entire growth process. Additionally, an introduction of either the Al2O3 or AlN before the GaN deposition could improve the surface morphology of the GaN deposited on Kapton.