The rapid thermal oxidation (RTO) technique has been physically and electrically evaluated on single crystal and amorphous silicon (α‐Si). Data on interface width, oxidation kinetics, and recrystallization kinetics as well as the conduction characteristics are reported for oxidized amorphous silicon. Our results indicate the RTO oxide grown on amorphous silicon is a film with peculiar behavior. By the use of a 250 Å thick oxide, no Fowler–Nordheim conduction is activated at ∼5 MV/cm, and no evidence of conduction is registered until a field of 6 MV/cm (breakdown field). The point‐to‐point film thickness uniformity results are better than that obtained from furnace oxidation on polysilicon. We suggest this to be related both to α‐Si used as a starting material, and to the short oxidation time. A special double metal capacitor test has been proposed and successfully used in order to study the electrical characteristics without any drawback on sample morphology. Based on our experimental results we consider RTO on amorphous silicon as a suitable technique to be used in multipolysilicon device application.