Ambient Pressure Influence on the Electrical Resistance of Tracks Fabricated by Picosecond Laser Pulses on the Surface of AlN Ceramic

Abstract

Herein, results are presented on the air pressure influence on the resistance of surface structures formed by picosecond processing of aluminum nitride ceramic. It is found that scanning the ceramic surface by laser radiation at the wavelengths of 1064 and 355 nm emitted by a neodymium‐doped yttrium aluminum garnet laser system can produce conductive lines. The resistance value is measured of structures fabricated under different processing conditions related to varying the laser fluence, pulse overlapping, and wavelength at different ambient air pressures from 10−4 Torr to atmospheric pressure. Based on the obtained dependences, the processing parameter windows are defined, allowing formation of a conductive material. It is demonstrated that changing the experimental conditions may change the resistance value by several orders of magnitude. The ambient pressure also affects the morphology of the ablated zones, with different structures being observed, including formation of ripples. The analyses performed of the processed surface indicate that conductivity arises from the presence of aluminum following a thermally induced ceramic decomposition. The influence of the gas flow during the laser processing on the resistance and the possibility of laser scribing of the ceramic are also experimentally estimated.