N‐type (P, Sb) and p‐type (B) doping of hydrogenated amorphous Si by reactive rf co‐sputtering

B, P or Sb were doped into amorphous silicon films by the reactive radio‐frequency co‐sputtering method. The targets used were composed of silicon wafers and small about 1 mm thick chips of the respective impurity element, which were attached to the silicon wafers with silver powder cement and epoxy resins. Argon and hydrogen partial pressures used were 5 × 10 –3 and 5 × 10 –4 torr, respectively. The impurity concentration in the film was determined by secondary ion mass spectroscopy for B and P and by He backscattering spectroscopy for Sb. The substrates were kept at 200–250 °C during deposition. Raman spectra revealed that films prepared even at 250 °C were amorphous. Heterostructures, where P‐, Sb‐ or B‐doped films were deposited on p‐ or n‐type Si, exhibited good rectification characteristics of n diodes. It has been shown that the co‐sputtering method can produce low‐resistivity p‐type (B) and n‐type (P) a‐SH films for relatively low concentrations of B and P, respectively.