| 摘要 |
PURPOSE:To reduce the irregularity of impurity distribution on a variable diode and minimize the characteristic irregularity thereof by employing an arsenic as first n- type impurity and using the arsenic for the main component of the shallow portion of n-type impurity distribution. CONSTITUTION:An n-type region is formed with two types of n-type impurities. In the shallow portion of the n-type region are existed a first n-type impurity having low diffusion coefficient such as, for example, an arsenic as a main component, and a second n-type impurity having high diffusion coefficient such as, for example, phosphorus as sub component. Further, in the deep region the depth thereof is increased, and the first n-type impurity amount is gradually reduced, and the second n-type impurity finally occupies 100% of n-type impurity. |
