IMPURITY DIFFUSING METHOD, SEMICONDUCTOR DEVICE, AND MANUFACTURE OF THE DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce the area of the peripheral area of an active area including guard rings. SOLUTION: In a semiconductor layer 35 which is laminated upon a substrate and in which an N-type impurity is added at a preset first impurity concentration, the impurity concentration of an area W1 surrounding an active area 36 containing a semiconductor element is increased from the first concentration by further adding the N-type impurity to the area W1. Then a P-type impurity is added to a plurality of annular areas surrounding the active area contained in the area W1 in nearly concentric states and diffused to a preset first depth. Consequently, guard rings 39-41 containing the P-type impurity and added layers 43-45 adjacently formed to the rings 39-41 are formed. The intervals among the rings 39-41 are narrower than those among the conventional guard rings and the area of the peripheral area including the guard rings is smaller than that of the conventional peripheral area.