On the study of electrical isolation of multi-layer GaAs planar doped barrier diode structures by proton bombardment

The electrical isolation in multi-layer GaAs planar doped barrier diode (PDBD) structures produced by proton bombardment was investigated. 250 keV proton implants were performed at doses of 5×10¹⁴ cm^-2 and 1×15 cm^-2. RTA annealing test were conducted from 50 to 500°C. It was found that the optimum annealing temperature is around 200°C, corresponding to a maximum sheet resistance R_sh of 3×10⁸ Ω/sq in the sample irradiated to a dose of 1×10¹⁵ cm^-2. The results indicate that for a single bombardment of a PDBD layer structure, very high R_sh was achieved. However, in both samples, R_sh starts to decrease at relatively lower annealing temperature comparing with a single GaAs sample bombarded with the same condition. Another annealing test was conducted on the sample irradiated to a dose of 1×10¹⁵ cm^-2, after removing the surface layer by etching to a depth of 0.23 μm. The thermal stability of the isolation improved to 400°C.