Dm. Ritchie et al., SILICON DELTA-DOPED ALGAAS BY LOW-PRESSURE METALORGANIC VAPOR-PHASE EPITAXY, Journal of crystal growth, 145(1-4), 1994, pp. 447-454
Delta doping of Si in Al0.22Ga0.78As by low pressure metalorganic vapo
r phase epitaxy has been explored for growth interruption times rangin
g from 10 to 60 s and for varying SiH4 partial pressures of 7.8 x 10(-
4) and 1.2 x 10(-3) mbar. The resultant sheet concentrations were line
ar with both time and SiH4 content up to saturation at 3.6 x 10(12) cm
(-2). The full width at half maximum versus sheet concentration was fo
und to correspond to theoretical predictions, indicating the absence o
f diffusion, with a minimum value of 60 Angstrom for a sheet concentra
tion of 3.6 x 10(12) cm(-2). For Si doses higher than 1 x 10(-2) ml Si
H4, an increase in full width at half maximum (FWHM) was observed. Pse
udomorphic high electron mobility transistor device results show a 300
K channel mobility of 3030 cm(2)/V.s with a sheet concentration of 2.
7 x 10(12) cm(-2). The maximum extrinsic transconductance of such devi
ces was 400 mS/mm with a corresponding saturation current of 360 mA/mm
for 0.5 mu m gate length devices.