Selective SiGe and heavily As doped Si deposited at low temperature by atmospheric pressure chemical vapor deposition

Abstract

Selective epitaxial Si with added As for n-type doping or Ge for band gap modulation can be deposited in an ultraclean atmospheric pressure chemical vapor deposition system down to temperatures as low as 550–750 °C. Depositions are carried out in a hydrogen ambience using dichlorosilane, HCl, and arsine or germane. The additives, arsine and germane enhance the Si deposition rate at low temperatures so that practical deposition rates can be achieved. HCl, which is used to control deposition selectivity with respect to oxide or nitride, decreases the deposition rate so that final growth rates are in the range 1–5 nm/min. Rutherford backscattering spectrometry was used to measure As concentrations as high as 1×1021/cm3 and Ge concentrations as high as 50%. A selective growth process for SiGe has been used to grow p-type metal–oxide–semiconductor field effect transistors and resonant tunneling diodes which display excellent device characteristics.