Hydrogen in metallo-organic chemically vapor-deposited ZnS thin films determined by nuclear resonance reaction analysis

Abstract

Nuclear resonance reaction analysis was used to determine hydrogen concentrationin polycrystalline metallo-organic chemically vapor-deposited ZnS films produced at low substrate temperatures and pressures. This method of hydrogen content determination is quantitative and non-destructive. Other available depth profile methods, such as secondary-ion mass spectroscopy (SIMS), are destructive and of limited quantitative use, as SIMS depends upon knowing accurate ionization yields for each type of matrix studied. Also, the nuclear resonance reaction analysis technique is not susceptible to vacuum artifacts associated with ion-sputtering techniques. Alteration of the H 2S-to-(CH 3) 2Zn flow rate ratio of reactants indicates that the hydrogen in the ZnS films is associated with the dimethylzinc, and not the hydrogen sulfide reactant. Variation in the substrate deposition temperature T s resulted in the decreased hydrogen concentration at increased T s (in the range 50–150°C). Hydrogen concentrations varied from about 1 × 10 20 to 2.0 × 10 21 atoms cm −3.