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

摘要

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 x 10(-3) and 5 x 10(-4) tort, 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 degreesC during deposition. Raman spectra revealed that films prepared even at 250 degreesC were amorphous. Heterostructures, where P-, Sb- or B-doped films were deposited on p- or n-type Si, exhibited good rectification characteristics of p-n diodes. It has been shown that the co-sputtering method can produce low-resistivity p-type (B) and n-type (P) a-Si: H films for relatively low concentrations of B and P, respectively. [References: 13]