Laser fabrication of silicon carbide light emitting diodes

Abstract

With the shrinkage in the size of the semiconductor devices, greater shift has been observed towards use of lasers, electron and x-ray beams and advanced optics for small area device fabrication. A novel laser direct-write doping and metallization technique provides a single step approach for processing wide bandgap materials for electronic and optoelectronic device applications, which are difficult to dope using conventional techniques. Laser doping opens the opportunity to use unconventional dopants for customizing emission wavelength. It effectively reduces the number of fabrication steps and allows for selective area doping and direct metallization without metal deposition. To demonstrate this technology a pulsed Nd:YAG laser (1064nm wavelength) was used to fabricate blue light emitting laser diodes in a silicon carbide (SiC) 6H:SiC (n-type) wafer substrates. A p-n junction was created by laser doping aluminum (p-type) and nitrogen (n-type) on clean SiC wafer. Pure indium wire was used to obtain good ohmic contacts. These devices were characterized by capacitance-voltage (C-V), current-voltage (I-V), and electroluminescence (EL) measurements. A narrow electroluminescence (EL) peak at 481.82 nm and broad EL peak around 498.8 nm wavelengths were observed with two different detectors, characterizing the p-n junction as a blue light emitter.