In Situ Phosphorus Doping of Germanium by APCVD

• Published in: ECS transactions Vol. 3; no. 7; pp. 599 - 609
• Main Authors: Dilliway, Gabriela, Van Den Boom, Ruud, Moussa, Alain, Leys, Frederik, Van Daele, Benny, Parmentier, Brigitte, Clarysse, Trudo, Simoen, Eddy R., Defranoux, C., Meuris, Marc M., Benedetti, Alessandro, Richard, Olivier, Bender, Hugo
• Format: Journal Article
• Language: English
• Published: 20.10.2006
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2355857

The in-situ fabrication of rectangular concentration-depth profiles of phosphorus in germanium, with electrically active concentrations approaching 10 20 cm -3 is reported. The growth method is atmospheric chemical vapor deposition using germane and phosphine with N 2 as carrier gas. Best results have been achieved using a relatively low growth temperature of 350ºC and a low PH 3 /GeH 4 flow ratio, enabling a high concentration of P to be incorporated substitutionally. No P clusters are visible in high-angle annular dark-field STEM images. The results show excellent crystalline quality and acceptable surface uniformity, achieved with growth rates in the range of 5-10 nm / min. There is evidence that further improvements in active concentrations may be achievable by a further reduction in growth temperature and optimization of the gas flow conditions. The process holds promise for future n + junction fabrication in germanium.