SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device and a method of manufacturing the same capable of suppressing fluctuation in current-voltage characteristic in a linear region of a MOS transistor.SOLUTION: A semiconductor device includes: a silicon substrate 1; a gate oxide 11 provided on the silicon substrate 1; a gate electrode 13 provided on the gate oxide 11; n-type source 21 and drain 23 provided below both sides of the gate electrode 13 in the silicon substrate 1; and an n-type drift layer 5 provided in the silicon substrate 1 from below the gate electrode 13 to the drain 23. The drift layer 5 includes a first drift layer 5a which is disposed below the gate electrode 13 to contact with the gate oxide 11, and a second drift layer 5b which is disposed between the first drift layer 5a and the drain 23. An n-type impurity concentration in the first drift layer 5a is higher than an n-type impurity concentration in the second drift layer 5b.