SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To improve the operation characteristics and reliability of a semiconductor device, at the same time, to reduce power consumption, the number of processes, and manufacturing costs, and to improve a yield by making appropriate the structure of a TFT being arranged in various circuits according to the function of the circuits. SOLUTION: In LDD regions 207, 215, 211, 219, 223a, 223b, and 229 overlapping with the gate electrode of a TFT, concentration inclination where the concentration of an N- or a P-type impurity element is increased is provided while the LDD regions approach source drain regions 208, 212, 216, 220, 226, 209, 213, 217, 221, 225, and 227. To form the LDD regions with the concentration inclination of the impurity element, the gate electrode with a tapered part is provided, and the ionized N- or P-type impurity element is accelerated by an electric field, is allowed to pass through the gate electrode and a gate insulating film 142, and is added to a semiconductor layer.