MANUFACTURE OF THIN FILM TRANSISTOR

摘要

PURPOSE:To obtain preferable contact characteristic and reproducibility and to provide the manufacture of a thin film transistor in simple steps by irradiating a laser light from behind a light transmission insulating substrate to decompose reaction gas, and selectively removing an N<+> type Si layer covered on a conductive material layer by radical generated as above. CONSTITUTION:Since laser light 10 passes through an N<+> type Si layer, fluorine or chlorine reaction gas is decomposed in the opening 11 of an opaque conductive material layer 2 to generate fluorine radical or chlorine radical. The fluorine or chlorine radical reacts with the N<+> type Si layer 3 to proceed an etching. Here, reaction gas pressure is controlled to reduce the mean free stroke of the fluorine or chlorine radical, thereby locally limiting the etching only to the vicinity of the position where the radical is generated. Accordingly, the etching is not proceeded at a part covered on the layer 2, but only the layer 3 covered on the opening 11 for transmitting the light 10 is selectively removed.