Abstract: A technique for accurately and repeatably measuring the depths of junctions between adjacent layers in a semiconductor wafer, even when the depths are relatively shallow. A groove is formed in the surface of the wafer, with a cylindrical grooving tool that is inclined to the planar surface of the wafer, to form a groove that is tapered in width and depth. The wafer is then conventionally treated to enhance the contrast between the layers as they are exposed on the groove surface. Since each planar junction intersects the groove surface at an angle, the corresponding junction line appears as a part of an ellipse, and exhibits a well defined peak at the center of the groove. Direct measurement of the depth of the groove at this point, using a standard profilometer, provides the desired junction depth.

Abstract: A high voltage, fast recovery time P-I-N diode is described in which the wafer used to form the device has a central depression. The central depression causes avalanche breakdown to occur preferably at the center of the device and through the bulk of the device rather than at the device edge which could irreversibly damage the device. The central depression also distorts the electric field lines as they terminate on the device edge so that they are more linearly distributed along the edge, thereby increasing the ability of the device to withstand breakdown at the edge of the device.

Abstract: A process is described for the particular control of process variables to produce any predetermined impurity concentration within a semiconductor body according to the relation ##EQU1## WHERE .differential.M/.differential.T IS THE FLUX OF IMPURITIES AT ANY TIME T, X IS THE DEPTH INTO THE SEMICONDUCTOR BODY, AND D(t) is the difficulty of the impurity as a function of time.