Upside-down fabricated GaP monolithic display

Abstract

An upside‐down fabricated GaP monolithic display having p‐n junctions formed by zinc diffusion is developed and the feasibility of practical use studied. In this device, the zinc diffusion is performed at a temperature in the vicinity of 650 °C to increase the efficiency. The device front plane with the p‐n‐junction segments faces the substrate upon which individual digits are assembled, and the light emitted from the p‐n junctions travels through the GaP chip and exits from the polished back plane, which faces the observer. The individual wire bonding of each segment is eliminated using flip‐chip technique. It is thought that this device is the most suitable for practical use.