Fundamental Origin of Si Surface Defects Caused by Laser Irradiation and Prevention of Suboxide Formation through High Density Ultrathin SiO2

Abstract

This research investigates surface damage in electronic devices from laser irradiation, particularly focusing on voids, cracks, and vacancies. We discovered that applying a high-density ultrathin SiO2 layer effectively prevents such defects. Atomic Force Microscopy (AFM) analysis showed a significant reduction in surface roughness, with the Rq factor value dropping to 0.158 nm in samples coated with this SiO2 layer. Additionally, X-ray Photoelectron Spectroscopy (XPS) was used to study suboxide formation in the Al2O3/Si structure, revealing insights into defect origins. Electrical tests indicated a substantial decrease in laser-induced damage, evidenced by a leakage current density reduction to 2.4 × 10−6 A/cm2, markedly lower than uncoated samples. Post-metallization annealing (PMA) further improved results, with the interface state density decreasing to 0.63 × 1012 atoms eV−1 cm−2. Our findings highlight the effectiveness of the high-density ultrathin SiO2 layer in mitigating surface defects caused by continuous wave (CW) laser irradiation, promising significant advancements in electronic device manufacturing through potential application in CW laser annealing processes.