Abstract
High resistivity silicon doped copper compensated gallium arsenide (GaAs:Si:Cu) has been studied as a bulk optically controlled semiconductor switch (BOSS) material. Three different diffusion techniques, semi-closed tube, closed tube, and leaky tube, were used to diffuse copper in GaAs. The influence of processing conditions, specifically, arsenic vapor pressure during diffusion of copper on switch photoconductivity is investigated. Photoinduced current transient spectroscopy (PICTS) and room temperature Hall measurements were used to characterize the copper diffused samples. It is seen that the arsenic vapor pressure during diffusion has a distinct effect on the copper compensation of the GaAs:Si crystal. Samples diffused without any arsenic and under low arsenic pressure (0.08 am.) were found to be n-type, and those diffused at higher arsenic pressure (1.0 atm. and 7.4 atm.) were found to be p-type. Also, the conductivity of the samples changed as a function of the arsenic vapor pressure. The dependence is similar to that of conductivity on temperature. Among the samples annealed using the three different diffusion systems, those annealed using the leaky tube diffusion system showed the best tun-on performance under low power laser excitation.
Published Version
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