Zinc diffusion from spin-on glass for the formation of low-resistance Schottky contacts to p-type GaInAs

A systematic study of zinc incorporation as a function of both time and temperature of heat treatment has shown that the surface zinc concentration in MOVPE p-type GaInAs can be increased from an as-grown maximum of 2*1019 to approximately 1*1020 atoms/cm3 by diffusion from a spin-on glass source. Specific contact resistance values much lower than 1*10-5 Omega cm2 have been achieved after such diffusion. These values were found to depend on the type of p-doping elements used in the as-grown double heterostructures. Light-emitting devices incorporating such low-resistance contacts have predicted lifetimes in excess of 300 years. An advantage on the spin-on glass diffusion process is its suitability for large-scale device production.