engleski

Damage accumulation in gallium arsenide during silicon implantation near room temperature

Damage accumulation in Si-implanted GaAs has been characterized by ion channeling and Raman scattering as a function of implant temperature, dose, and dose rate. The damage was found to be extremely sensitive to temperature near room temperature (RT), such that an implant dose of 61014 Si/cm2 which produced a peak damage fraction of 94% at 20degreesC gave only a 15% damage fraction at 30degreesC. Such a sharp damage transition obviously has important implications for controlling the activation of dopants implanted at RT. One consequence is a strong dependence of the damage on dose rate near RT: the damage increases with dose rate as the dose rate is increased over nearly two orders of magnitude. Comparison of ion channeling results with Raman scattering measurements indicates that the morphologies of the dose-rate-dependent and dose-dependent damage components in RT implants are distinct, i.e., the rate-dependent component primarily consists of crystalline defects, while the dose-dependent damage has a large amorphous contribution. These experimental observations are discussed in terms of the competition between different damage nucleation and growth mechanisms as a function of the implant parameters (16 References).

semiconductor; implantation; room temperature; ion channeling; Raman scattering; activation; dopants; damage; crystalline defects; amorphous; GaAs:Si.

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