Type Conversion of InSb from p to n by Ion Bombardment and Laser Irradiation

There are three approaches made form an n + -layer on p-InSb. They are (1) proton or (2) Si ion bombardment with an energy of 60 or 100 keV and a dose of 1∼2×10 15 cm -2 , and (3) Q -switched Nd: YAG laser irradiation. Effects are investigated of subsequent isochronous annealing for 30 min. Both (1) and (3) directly form an n + -layer without annealing, while (2) initially produces a p-layer which becomes n + after annealing above 200°C. The resultant n + -layer obtained by (2) and (3) can withstand the annealing up to 350°C, whereas that by (1) is restored to p above 100°C. Mesa-type diodes at 77 K prepared from (2) and (3) show forward current density given by J =1×10 -8 exp ( q V /1.7 k T ) A/cm 2 and junction capacitance vs. reverse bias expressed by C ∝( V D +| V |) -0.43 with diffusion potential V D =0.2 V.