Semiconductor device, fabrication method for semiconductor device, power supply apparatus and high-frequency amplifier
A semiconductor device is configured including a p-type back barrier layer provided over a substrate and formed from a p-type nitride semiconductor in which Mg or Zn is doped, a nitride semiconductor stacked structure provided over the p-type back barrier layer, the nitride semiconductor stacked structure including an electron transit layer and an electron supply layer, a source electrode, a drain electrode and a gate electrode provided over the nitride semiconductor stacked structure, and a groove extending to the p-type back barrier layer.
1. A fabrication method for a semiconductor device, comprising:
forming a p-type back barrier layer from a p-type nitride semiconductor in which Mg or Zn is doped over a substrate;
forming a nitride semiconductor stacked structure including an electron transit layer and an electron supply layer over the p-type back barrier layer;
forming a source electrode, a drain electrode and a gate electrode over the nitride semiconductor stacked structure;
forming a groove extending to the p-type back barrier layer; and
performing an anneal process for desorbing hydrogen from the p-type back barrier layer through the groove to activate the p-type back barrier layer.
2. The fabrication method for a semiconductor device according to claim 1 , further comprising providing a hydrogen occlusion alloy in the groove before the anneal process is performed after the groove is formed; wherein
in the performing the anneal process, hydrogen is desorbed from the p-type back barrier layer using the groove and the hydrogen occlusion alloy formed in the groove to activate the hydrogen occlusion alloy.
3. The fabrication method for a semiconductor device according to claim 2 , wherein the hydrogen occlusion alloy contains any one of Ti, Zr, Pd and Mg.
4. The fabrication method for a semiconductor device according to claim 1 , wherein, in the forming the groove, the groove is formed so as to extend from the surface of the nitride semiconductor stacked structure to the p-type back barrier layer.
5. The fabrication method for a semiconductor device according to claim 1 , wherein, in the forming the groove, the groove is formed in an active region or in the proximity of the active region.
6. The fabrication method for a semiconductor device according to claim 1 , wherein, in the forming the source electrode, drain electrode and gate electrode, the source electrode or the drain electrode is formed over the groove.
7. The fabrication method for a semiconductor device according to claim 1 , wherein, in the forming the groove, the groove is formed so as to extend from the back face of the substrate to the p-type back barrier layer.