JPS57138158A - Formation of conductive thin film - Google Patents

Abstract

PURPOSE:To enable to form a pattern on the conductive thin film pattern very easily by a method wherein a laser beam is irradiated on the prescribed region of the surface of an insulating oxide in a non-oxidizing atmosphere, and this region is transformed into a conductive substance by adding the constituent element of an oxide. CONSTITUTION:An SiO2 film 2 is formed by oxidating the surface of an Si substrate 1 at a high temperature, and a CO2 laser beam 3 is irradiated on the prescribed region in an H2 atmosphere. At this time, the laser beam is absorbed easily by SiO2, but as it is not absorbed by Si, no effect is given to the substrate. Through these procedures, the film 2 of the section whereon the laser beam was irradiated is heated up, the reduction of SiO2+2H2 Si+2H2 is generated, and the region where the laser beam was irradiated is converted to an Si film 4. As this film 4 is in a polycrystallined state and does not contain active impurities, the film 4 has a high specific resistance. Therefore, when a source and drain regions are formed, impurities are doped and required conductivity is given, and the film suitable for a gate electrode can be obtained.