Laser doping of silicon carbon and pin diode fabrication Available to Purchase

Direct write laser doping is used to fabricate a PIN diode in a semi-insulating 6H-SiC wafer comprised of a p-type zone in one surface and an n-type zone in the opposing surface separated by an insulating region. Ohmic and Schottky contacts ate fabricated by a laser metallization technique which converts silicon carbide to a conductive phase without the addition of metal. Trimethylaluminum (TMA) and nitrogen are the precursors used to laser dope p-type and n-type regions, respectively. Laser doping of nitrogen in silicon carbide epilayers and single crystal substrates increase the dopant concentration by two orders of magnitude and produce both deep (500-600 nm) and shallow (50 nm) junctions, respectively. Laser-assisted effusion/diffusion is used to dope aluminum in silicon carbide wafers and a 150 nm p-type doped junction can be fabricated in semi-insulating 6H-SiC and n-doped 4H-SiC wafers. At a reverse bias of 40V, the leakage current density is 8.3×10⁻³ A/cm². The leakage current density increases from 6.9×10⁻⁴ A/cm² at 20°C to 1.3×10⁻² A/cm² at 300°C at reverse bias of 20V. The average dopant concentration in the p-region is calculated as 7.46 ×10¹⁶ cm⁻³ and the Schottky barrier height formed by the p-type zone is 0.75 eV based on the C-V characteristic. This laser-fabricated diode is intended for use in high-temperature, high-voltage and high-frequency switching and sensing applications.