Study of shallow donor formation in hydrogen-implanted n-type silicon
Formation of shallow donors has been studied in 100 keV hydrogen-implanted n-type silicon with a dose of . Annealing experiments are made in the temperature range 100 to C for 30 min. Gold Schottky contacts are fabricated on these samples to obtain carrier profiles. The hydrogen profiles are measured by secondary-ion mass spectroscopy. The zero-bias depletion layer width measured at 90 K is below the pre-implantation value in the annealing temperature range 300 to C, indicating the introduction of shallow donors. Two kinds of shallow donor (HS1 and HS2) are found to be formed in this annealing temperature range from carrier profile measurements. The HS1 donor is observed at the annealing temperatures around C and shows a concentration peak at the depth around the mean projected range of implanted hydrogen. The HS2 donor is observed in the annealing temperature range 350 to C and spreads toward the surface with almost flat profiles. Comparison of carrier and hydrogen profiles indicates that the HS1 donor is hydrogen related. The possibility that the HS2 donor is also hydrogen related is discussed.