| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which can reduce manufacturing processes while achieving high withstand voltage and low on-resistance.SOLUTION: In a semiconductor device manufacturing method, when ion implantation is performed by using an ion implantation mask with its opening width changed, by utilizing a matter that when the opening width of the ion implantation mask becomes not greater than a predetermined dimension, an impurity concentration in a diffusion region to be formed changes in proportion to the opening width, a width of the opening to be formed on a gate electrode side is decreased and a width of the opening to be formed closer to a drain region side than the opening to be formed on the gate electrode side is increased, so that a drift layer having a gradient concentration profile is formed by one-time formation of the ion implantation mask and one-time ion implantation. |
