Etch Mechanism of AlN Thin Film in Cl2/Ar Inductively Coupled Plasma

• Published in: Transactions on electrical and electronic materials Vol. 23; no. 5; pp. 569 - 577
• Main Authors: Woo, Jong-Chang, Kim, Dong-Pyo, Kim, Gwan-Ha
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Electrical and Electronic Material Engineers (KIEEME) 2022
• Subjects: Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Regular Paper; Ar Plasma; Cl; AlN; Etching; X-ray photoelectron spectroscopy; Aluminum nitride
• ISSN: 1229-7607; 2092-7592
• DOI: 10.1007/s42341-022-00408-6

The etching characteristics of aluminum nitride (AlN) were investigated with the etch rate of AlN thin film and the selectivity of AlN to SiO 2 in an inductively coupled Cl 2 /Ar plasma. The AlN etch rate was linearly increased with increasing bias power. However, the AlN etch rate appeared a non-monotonic behavior with an increasing Cl 2 ratio in the Cl 2 /Ar plasma and pressure. Since the AlN thin films were of the relatively high melting point and binding energy, the high energetic positive ions were required to break Al-N bonds and to form volatile etch by-products, resulting in a high etch rate. The chemical condition on the surfaces of AlN thin films was investigated with X-ray photoelectron spectroscopy and the volatile etch by-products were observed. As a result, AlN etching mechanisms have been suggested to be an ion-enhanced chemical etching.