Optoelectronics devices on silicon carbide

Semiconductor materials with excellent physical stability to various sorts of effects and with high thermal conductivities for applications to high-temperature, high-power, and microwave devices have come to be applied more widely with the growing need for optoelectronics devices. Until recently, silicon carbide has not been widely used as the initial material for manufacturing optoelectronics devices because of its high price, large parameter-spread, small size, high temperature for diffusion processes, and so on. The characteristics of the silicon-carbide optoelectronics devices have been investigated, especially, for improvement in their operational characteristics. This includes the influences of surface processing, the formation method for the p-n junctions, and the contacts on the properties of light-emitting devices (LEDs) used as light sources for optical-fiber communication lines. p-n junctions were made by diffusion at 1600 degrees C by using the method of divorced-joint diffusion of O and Al, or of Al and B, with which effective LEDs for yellow-red, yellow, and green-yellow light are fabricated. We also fabricated Al+ ion-implanted p-n junctions in 6H-SiC and investigated their characteristics for an effective green LED. The brightness of the ion-implanted p-n junction was found to be two orders higher than that of the diffusion p-n junction, and the best value was 2000 similar to 10000 cd/m(2). The ion-implanted structures showed a high stability of light in the temperature range of 77 similar to 600 K and narrow lines in the electroluminescence spectra at relatively small currents.