Interdigitated multipixel arrays for the fabrication of high-power light-emitting diodes with very low series resistances

We report on the fabrication of high-power light-emitting diodes (LEDs) with very low series resistance by employing a mask design consisting of interdigitated multipixel arrays. The reduction in the series resistance was mainly achieved by reducing the bulk n resistance and the n-contact resistance by increasing the effective perimeter of the mesa. The small separation of the p and n contacts of the individual pixel improved lateral current spreading. The distributed array of pixels also resulted in improved thermal management, effectively rendering high continuous-wave (cw) drive current operation. Significant improvement in electrical and optical performances was observed when the mask was applied to a 400 nm InGaN/GaN violet LED wafer, compared to a standard square-shaped LED with equal active area and fabricated from the same epitaxial wafer. Series resistance of less than 1 Omega was measured for 300 mu m devices. A peak output power of 115 mW was obtained at 3.15 A cw drive current for the unpackaged device. (c) 2006 American Institute of Physics.