Laser conversion of electrical properties for silicon carbide device applications

Abstract

A direct conversion technique has been demonstrated to produce highly conductive tracks on silicon carbide by irradiating it with a laser beam. It is found that laser irradiation of insulating silicon carbide substrates decreases its resistivity from 1011 to 10−4 Ω cm. Scanning electron microscopy of laser-irradiated α-silicon carbide substrate reveals dispersed globules on the irradiated track. The atomic force microscopic images of the tracks indicate the conversion of larger structures into smaller, more round-shaped structures suggesting the formation of globules. However, laser irradiation of silicon carbide conductors in the presence of pure oxygen transforms the conducting track into an insulator. The effect of annealing on the electrical properties of the laser-generated conducting tracks is also examined. This technique provides a means of directly writing conducting and insulating tracks on silicon carbide to produce electronic devices for high temperature applications.

Decoupling of silicon carbide optical sensor response for temperature and pressure measurements

“…39,40 The optical absorber was produced inside the SiC wafer as shown in Fig. 2 and 3 are multivalued functions of temperature and pressure, which cannot be used directly to measure temperature and pressure.…”

Characteristics of 6H-silicon carbide PIN diodes prototyping by laser doping

“…12,13 A laser conversion technology, first reported by Quick, 14 was investigated [15][16][17][18] to dope SiC without high-temperature annealing as an alternative to conventional ion implantation. Sengupta et al 15 generated conductive tracks on an insulating SiC substrate surface without requiring any metallization, and Salama et al [16][17][18] fabricated Schottky and Ohmic contacts, n-and p-doped regions using the LISPD method and a new effusion-diffusion technique, and Schottky diodes using 4H-SiC wafers. They observed no change in the surface roughness after their laser-doping experiment; however, they did not report if the laser-doping process creates any lattice damage in the wafers.…”

Fabrication of Silicon Carbide PIN Diodes by Laser Doping and Planar Edge Termination by Laser Metallization

“…[1] Ion implantation, the most common doping technique used for fabricating SiC devices, generates implantation-induced defect centers in the wafer and high annealing temperatures are required to remove these defects and to electrically activate the dopants. However, there are still some technology barriers for silicon carbide device fabrication such as dielectric deposition, etching, oxidation, etc.…”

“…A laser conversion technology, first reported by Quick [3] was investigated [1,[4][5][6][7][8][9] to laser direct metallize without metal deposition and laser dope in SiC without high temperature annealing, as an alternative to the conventional ion implantation, and fabricate Schottky diodes and PIN diodes on 4H-and 6H-SiC wafers. This paper presents experimental results on the improved performance of PIN diodes fabricated by laser doping using three methods; reducing the active area of the diode, annealing and edge termination by laser metallization.…”