Research on rapid thermal annealing of ohmic contact to GaAs

In order to increase heat dispersion and improve power and reliability of GaAs-based semiconductor lasers, the rapid thermal annealing (RTA) of ohmic contact to GaAs were optimized. The ohmic contact multi-layer metals of Ni/AuGe/Ni/Au on n-GaAs and Ti/Pt/Au on p-GaAs at annealing temperature of 380~460°C and annealing duration of 40s~80s were calibrated. The rectangular transmission line model (RTLM) were adopted to calculate the specific contact resistance. For n-GaAs ohmic contact, the optimized contact resistivity is 2.76×10-6 Ω·cm² at annealing temperature of 420°C for 60s. Under the same annealing conditions for p-GaAs, the contact resistivity is 3.91×10-5 Ω·cm². The 808nm laser diode with double-side light output using the optimized RTA conditions, the maximum output power is more than 3W at operating current of 4A.