S.S. Kular

Electrical, Rutherford backscattering and transmission electron microscopy studies of furnace annealed zinc implanted GaAs

Abstract Electrical, Rutherford backscattering and transmission electron microscopy measurements have been carried out on GaAs samples implanted with 150 keV, 1.10 15 zinc ions/cm 2 and furnace annealed in the temperature range from room temperature to 900°C. A correlation between three types of measurement technique was established and four distinct annealing stages have been identified. For perfect recrystallization and maximum electrical activation an annealing temperature of 900°C is required. The maximum peak hole concentration was in the range 1–2.10 19 holes/cm 3 .

The electrical properties of zinc implanted GaAs

Abstract The electrical properties of zinc implanted GaAs have been measured as a function of ion dose, ion energy, implant temperature and annealing temperature and time using either evaporated aluminium layers or pyrolytically deposited Si 3 N 4 as the encapsulant during annealing. The electrical profiles depend on all the above variables and thus profiles can be tailored by varying the relative magnitudes of these parameters. It is important to note that hole concentrations in excess of 1 × 10 19 cm −3 can be obtained following an anneal at temperatures as low as 650°C. Also, at the same annealing temperature, profile depths can be varied from 0.2 to about 1 μm by correct choice of implantation parameters. Aluminium coatings are acceptable for annealing temperatures up to 700°C but Si 3 N 4 is required at higher temperatures.

Laser annealing of ainc implanted GaAs

Abstract GaAs samples implanted with 1.10 15 zinc ions/cm 3 have been annealed using pulses from a ruby laser operating in the freely generated mode. The percentage electrical activities and peak carrier concentrations were found to depend on the implant temperature, the laser energy density and the number of pulses. The maximum hole concentration measured was about 1.10 20 cm −3 following irradiation with four pulses of 3 J/cm 2 . Significant residual damage remained after single pulse irradiation at this energy density value. However, the carrier mobilities were similar to values for good single crystal GaAs.

A COMPARISON OF LASER – ANNEALED DONOR AND ACCEPTOR IONS IMPLANTED INTO GaAs

The use of a Q-switched ruby laser to anneal GaAs implanted with either donor (Se and Sn) or acceptor (Zn and Cd) ions has been studied using electrical, RBS and TEM measurements. Weight losses arising from laser annealing were found to be considerable for energy densities >0.3 J/cm 2 . When the effect of weight loss together with a diffusion coefficient of 5.10 –4 cm 2 /s for the implanted dopants is taken into account the results of the electrical and RBS measurements can be explained.