OPTIMIZATION OF THE TRADEOFF BETWEEN SWITCHING SPEED OF THE INTERNAL DIODE AND ON-RESISTANCE IN GOLD-IMPLANTED AND PLATINUM-IMPLANTED POWER METAL-OXIDE SEMICONDUCTOR-DEVICES

Diffusion of platinum and gold has been used to reduce minority-carrier lifetime in power metal-oxide-semiconductor devices in order to improve the switching characteristics of the internal diode. Gold thin-film deposition and gold- or platinum-ion implantation techniques have been adopted to realize the prediffusion source. For a given reduction in lifetime, the concomitant increase in the on-resistance of the device, as determined by the forward characteristics, is smaller in gold-implanted than in gold-deposited devices; an even smaller increase in on-resistance is obtained by using platinum implantation. Therefore, ion implantation of platinum in power MOS devices fabrication provides a better tradeoff between static characteristics of the devices and switching speed of their internal diodes.