SCHOTTKY BARRIER DIODE FORMED ON NITRIDE SEMICONDUCTOR SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To solve a problem that when an anode electrode 22 which forms Schottky contact and a cathode electrode 20 which forms ohmic contact are formed on a surface of a substrate on which a first nitride semiconductor layer 6 serving as an electron transit layer of a HEMT and a second nitride semiconductor layer 8 serving as an electron supply layer of the HEMT are laminated, a SBD (Schottky Barrier Diode) can be obtained but a leakage current is large and breakdown voltage is low.SOLUTION: In a Schottky Barrier Diode formed on a nitride semiconductor substrate, a region where a second nitride semiconductor layer 8 directly contacts the anode electrode 22 and a region where the second nitride semiconductor layer 8 contacts the anode electrode 22 via a fourth nitride semiconductor region 12b and a third nitride semiconductor region 10b exist in a mixed manner. By changing the fourth nitride semiconductor region 12b to a p-type, a leakage current can be inhibited. By using a nitride semiconductor having a bandgap larger than that of the second nitride semiconductor layer 8 for the third nitride semiconductor region 10b, the minimum value of a forward voltage where a forward current flows can be kept as low as possible.SELECTED DRAWING: Figure 1