Silicon delta-doped AlGaAs by low pressure metalorganic vapor phase epitaxy

• Published in: Journal of crystal growth 1994-12, Vol.145 (1), p.447-454
• Main Authors: Ritchie, D.M., Di Paola, A., Tromby, M., Dellagiovanna, M., Di Egidio, M., Vidimari, F.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities: doping, implantation, distribution, concentration, etc; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(94)91090-1

Delta doping of Si in Al 0.22Ga 0.78As by low pressure metalorganic vapor phase epitaxy has been explored for growth interruption times ranging from 10 to 60 s and for varying SiH 4 partial pressures of 7.8 X 10 -4 and 1.2 X 10 -3 mbar. The resultant sheet concentrations were linear with both time and SiH 4 content up to saturation at 3.6 X 10 12 cm -2. The full width at half maximum versus sheet concentration was found to correspond to theoretical predictions, indicating the absence of diffusion, with a minimum value of 60 Å for a sheet concentration of 3.6 X 10 12 cm -2. For Si doses higher than 1 X 10 -2ml SiH 4, an increase in full width at half maximum (FWHM) was observed. Pseudomorphic 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 12cm -2. The maximum extrinsic transconductance of such devices was 400 mS/mm with a corresponding saturation current of 360 mA/mm for 0.5 μm gate length devices.