Effect of laser irradiation passes for fabricating mid-wave infrared silicon carbide detectors
A Mid-Wave Infra-Red (MWIR) detector is developed by doping an n-type 4H-SiC with Ga using a laser doping technique. Doping is one of the challenges for silicon carbide (SiC) device fabrication due to its hardness, chemical inertness and the low diffusion coefficient of most impurities. A laser doping technique is chosen to dope 4H-SiC by gallium which is incorporated into the semiconductor as p-type dopants. The substrate is simultaneously heated with a continuous wave Nd:YAG laser of wavelength 1064 nm under the laser power, focal length, laser beam diameter and micro-stage speed were 10.5 W, 150 mm, 200 µm and 0.8 mm/sec respectively using metal-organic dopant precursor. The gallium dopant profile in the laser-doped SiC wafer is obtained by secondary ion mass spectroscopy and the maximum concentration of Ga in SiC wafer surface with 4 time of laser irradiation passes is found to be 6.251×1020 cm−3, which is two orders of magnitude higher than the reported value (6.0×1018 cm−3) and the dopant depth is a...