Substrate-dependent electrical properties of low-dose Si implants in GaAs

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Abstract
A comprehensive electrical study of low‐dose (1012−1013 cm−2) Si implants in both liquid‐encapsulated Czochralski (LEC) grown undoped and horizontal Bridgman grown Cr‐doped semi‐insulating GaAs has been made using Hall measurements. The optimum annealing temperature is 850 °C, and an apparent electrical activation efficiency of 90% has been achieved with room‐temperature implantation for both substrates. The carrier depth profiles are much broader and the peak concentrations are much lower than those expected according to the Lindhard–Scharff–Schiott (LSS) theory. Although the carrier profiles for both substrates agree with each other relatively well, the mobilities for the undoped substrates are significantly higher than those for the Cr‐doped substrates at all low doses.