| 摘要 |
PROBLEM TO BE SOLVED: To reconcile securing of withstand voltage and suppression of current collapse, while reducing warpage of a substrate, by controlling the carbon concentration in a group 13 nitride semiconductor layer.SOLUTION: A group 13 nitride semiconductor substrate includes a structure where an initial nucleation layer, a buffer layer, and an active layer, each composed of a group 13 nitride semiconductor, are laminated sequentially on one principal surface of a base substrate. The buffer layer has a laminated structure where a region V, a region V, a region Vand a region Vare formed, in this order, from the base substrate toward the active layer. Carbon concentration of the region Vis lower than the carbon concentration any of the region Vand region V. Carbon concentration of the region Vis higher than the carbon concentration of the region V, which is higher than the carbon concentration of the active layer.SELECTED DRAWING: Figure 2 |
