Patent ID: 8067278
Filing Date: 2011-11-29
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device, comprising: a first step of providing an amorphous semiconductor film including a catalyst element in at least a portion thereof, the catalyst element being capable of promoting crystallization of the amorphous semiconductor film; a second step of performing a first heat treatment on the amorphous semiconductor film so as to crystallize at least a portion of the amorphous semiconductor film, thereby obtaining a semiconductor film including a crystalline region; a third step of patterning the semiconductor film to form a plurality of island-shaped semiconductor layers including an island-shaped semiconductor layer of a p-channel thin film transistor and an island-shaped semiconductor layer of an n-channel thin film transistor, each of the plurality of island-shaped semiconductor layers including the crystalline region; a fourth step of forming a gate insulating film on the plurality of island-shaped semiconductor layers; a fifth step of forming a conductive film on the gate insulating film and shaping the conductive film to form a first gate electrode on the gate insulating film on the island-shaped semiconductor layer of the p-channel thin film transistor; a sixth step of doping the island-shaped semiconductor layer of the p-channel thin film transistor with an impurity element providing p-type conductivity using the first gate electrode as a mask so as to form a source region, a drain region and a gettering region capable of attracting the catalyst element; a seventh step of forming, on the conductive film, a mask that exposes a portion of the island-shaped semiconductor layer of the p-channel thin film transistor, covers the first gate electrode, and defines a second gate electrode formed on the island-shaped semiconductor layer of the n-channel thin film transistor; an eighth step of shaping the conductive film using the mask to form the second gate electrode; a ninth step of doping regions of the plurality of island-shaped semiconductor layers that are not covered with the mask, the first gate electrode or the second gate electrode, with an impurity element providing n-type conductivity, thereby further doping the gettering region of the island-shaped semiconductor layer of the p-channel thin film transistor with an n-type impurity while forming a source region and a drain region of the island-shaped semiconductor layer of the n-channel thin film transistor; and a tenth step of performing a second heat treatment so as to move at least a portion of the catalyst element in the island-shaped semiconductor layer of the p-channel thin film transistor to the gettering region thereof and at least a portion of the catalyst element in the island-shaped semiconductor layer of the n-channel thin film transistor to the source region and the drain region thereof; wherein a step of selectively thinning or selectively removing a portion of the gate insulating film on the gettering region of the island-shaped semiconductor layer of the p-channel thin film transistor is performed at least once at any point in time between after the seventh step to after the eighth step.