Patent ID: 6664145
Filing Date: 2003-12-16
Classification: G02F,H01L

Abstract:
A method of manufacturing a semiconductor device provided with a pixel TFT formed in a pixel portion and a driver circuit having a p-channel TFT and an n-channel TFT formed in the periphery of said pixel portion over the same substrate, said method comprising:forming a semiconductor layer containing a crystal structure over said substrate; forming a plurality of island-like semiconductor layers by selectively etching the semiconductor layer containing a crystal structure; forming a gate insulating film in contact with the island-like semiconductor layers; forming a conductive layer made of a heat-resistant conductive material over the gate insulating film; forming a gate electrode having a taper portion by selectively etching the conductive layer; forming a first impurity region having a concentration gradient of an n-type impurity element in a direction parallel to said substrate by doping the n-type impurity element at least into the island-like semiconductor layers that form the n-channel TFT of said driver circuit and the pixel TFT through the taper portion of the gate electrode and through the gate insulating film; forming a second impurity region by doping an impurity element that imparts n-type conductivity into the island-like semiconductor film that forms the n-channel TFT and the p-channel TFT of said driver circuit, using the gate electrode as a mask; forming a third impurity region having a concentration gradient of a p-type impurity element in a direction parallel to said substrate by doping the p-type impurity element into the island-like semiconductor layer that forms the p-channel TFT of said driver circuit through the taper portion of the gate electrode and through the gate insulating film, and of forming at the same time a fourth impurity region by doping an impurity element that imparts p-type conductivity, but not via the taper portion of the gate electrode; forming a first interlayer insulating film made of an inorganic insulating material above the n-channel TFT of said driver circuit, the pixel TFT and the p-channel TFT; forming a second interlayer insulating film made of an organic insulating material in contact with the first interlayer insulating film; and forming a pixel electrode having a light reflective surface to be connected to the pixel TFT, over the second interlayer insulating film.