MANUFACTURE OF ACTIVE MATRIX SUBSTRATE FOR LIQUID CRYSTAL DISPLAY DEVICE AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain an active matrix substrate for liquid crystal display device, which shows a stable driving characteristic by improving and uniformizing the thin-film transistor(TFT) characteristic of the substrate by improving the injecting accuracy of an impurity injected into the channel region required for controlling the TFT characteristic. SOLUTION: In the manufacturing process of a polycrystalline thin-film transistor on an insulating substrate 14, a protective film 11 of silicon oxide, etc., is formed in advance on a polycrystalline silicon semiconductor layer or on an amorphous silicon layer 12 before poly-crystallization and, after such an impurity as boron, etc., is injected into the polycrystalline silicon semiconductor layer, the protective film 11 is removed. Therefore, a channel region 15 in which the impurity concentration is controlled to a specific value can be obtained.