| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure and a method that reduce strain in a GaN thin film formed on a silicon substrate.SOLUTION: A semiconductor wafer comprises: a substrate; an aluminum nitride layer provided on the substrate; an aluminum gallium nitride provided on the aluminum nitride layer; and a gallium nitride layer provided on the aluminum gallium nitride layer. A laminate structure including the substrate, aluminum nitride layer, aluminum gallium nitride layer, and gallium nitride layer has compressive strain due to the aluminum nitride layer and gallium nitride layer at a growth temperature of the gallium nitride layer. Then tensile strain due to mutual difference in coefficient of thermal expansion among the substrate, aluminum nitride layer, aluminum gallium nitride layer, and gallium nitride layer and the compressive strain balance each other, so that the substrate has a flat shape.SELECTED DRAWING: Figure 5 |
