Laser‐doping of silicon carbide for p–n junction and LED fabrication

Abstract

AbstractThe high melting point and the limited diffusion of impurities in silicon carbide have greatly restricted the use of conventional ion implantation and furnace to incorporate and activate dopants. A laser doping technique overcomes these obstacles for doping silicon carbide and other wide band gap semiconductors. This paper presents the work on fabrication of p–n junction diodes and blue light emitting diodes using laser doping technique. A p–n junction was created by laser doping a silicon carbide wafer with aluminum (p‐type) and nitrogen (n‐type). Optical interferometer profilometer scan showed that there was no damage on the surface post laser doping. Secondary ion mass spectrometry (SIMS) was carried to estimate the dopant concentration and depth. The effects of laser doping on the current–voltage characteristics were studied. The junctions were characterized by capacitance–voltage and electroluminescence measurements. A broad electroluminescence peak was observed around 498.8 nm wavelength, characterizing the p–n junction as a blue light‐emitting diode. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)