Reduction of residual stress in AlN thin Films synthesized by magnetron sputtering technique

TL;DR

This study investigates how substrate temperature affects residual stress, crystal structure, surface morphology, and nanomechanical properties of AlN thin films synthesized by magnetron sputtering, revealing stress reduction and structural evolution.

Contribution

It provides new insights into controlling residual stress and crystal orientation in AlN films through substrate temperature variation during magnetron sputtering.

Findings

Residual stress varies from tensile to compressive with temperature.

Preferred a-axis orientation observed at 400°C.

Hardness ranges from 12.8 to 19 GPa.

Abstract

We report the reduction in residual stress of AlN thin films and also the crystal structure, surface morphology and nanomechanical properties of magnetron sputtered as a function of substrate temperature (Ts, 35 - 600 ?C). The residual stress of these films was calculated by sin2 technique and found that they are varying from tensile to compression with temperature (Ts). Evolution of crystalline growth of AlN films was studied by GIXRD and transmission electron microscopy (TEM) and a preferred a-axis orientation was observed at 400 ?C. The cross-sectional TEM micrograph and selected area electron difraction (SAED) of this film exhibited a high degree of orientation as well as a columnar structure. Hardness (H) measured by Nanoindentation technique on these films ranged between 12.8 - 19 GPa.