| 摘要 |
PURPOSE:To improve more a breakdown strength in a simple structure by a method wherein a semiconductor layer has an impurity concentration part, whose impurity concentration under the peripheral parts of a Schottky electrode is set lower than that under the central part of the electrode. CONSTITUTION:An n<-> layer 2b of an impurity concentration smaller than that of an n<-> type layer 2a is formed under the peripheral parts of a Schottky electrode 3. A depletion layer 5a is formed larger its width in the layer 2b than its width in the layer 2a because the impurity concentration of the layer 2b is smaller than that of the layer 2a. Thereby, the width of the layer 5a is unified so as to become small for field-effect concentration due to a surface charge in the surface part of the layer 5a, but the width, which is positioned in the vicinity of the surface of the layer 2b, of the layer 5a is still larger than that in the interior of the layer 5a. Accordingly, it is eliminated that a breakdown is caused in the surface of the layer 5a earlier than that in the interior of the layer 5a and a breakdown strength VB can be improved to a value which is determined by an intrinsic junction condition. |
