PURPOSE: To form a high-quality polycrystal silicon thin film without using an expensive heat-resisting glass substrate by forming the polycrystal silicon thin film on a light penetrable substrate at low temperatures, using the specified film formation gas and etching gas, not using hydrogen for a dilution gas.
CONSTITUTION: In the manufacture of a polycrystal silicon thin film transistor, a light penetrable substrate 1 is used. Also, silicon hydride is used for a film formation gas for forming a polycrystal silicon film and silicon fluoride or silicon chloride gas is used for an etching gas. Such reaction gas is discharged at the specified power intensity into a plasma and a polycrystal silicon thin film 2 is formed on the light penetrable substrate 1 which is kept to a constant temperature between about 100°C and 700°C. Under such condition, the thin film 2 of (100) orientation 30% or above, hydrogen content 2.5 atom % or below and fluorine content 3 atom % or below can be obtained. On the thin film 2, a source electrode 4 and a drain electrode 3 are formed and a gate electrode 6 is formed on or under a part of the polycrystal silicon thin film between the source and drain electrodes through an insulated film 5. Thus, the device is completed.
KAKIGI HISASHI
FUKUI KEITARO
