Chemical Vapor Deposition of Epitaxial Silicon‐Germanium from Silane and Germane: II . In Situ Boron, Arsenic, and Phosphorus Doping

Abstract

We have studied in situ boron, arsenic, and phosphorus doping of epitaxial silicon and layers grown on silicon substrates at 620°C and at very low pressure (∼7 mTorr) with silane, germane, and diborane, and arsine and phosphine diluted in silane as gas sources. Structural quality was chacterized by cross‐sectional transmission electron microscopy and the germanium and dopant depth profiles were probed by secondary ion mass spectrometry. The results confirmed that strained heterostructures with 13 atom percent germanium doped to and have been achieved. Phosphorus doped multilayer structures with highly perfect surface and silicon layers were also obtained. The addition of arsine and phosphine were found to severely degrade the growth rates of both silicon and layers. Germanium incorporation appeared to enhance the n‐type doping process by compensating the depressed growth rate resulted from surface poisoning and by improving the abruptness of dopant profiles. However, deposition of was not greatly affected by boron doping.