Semiconductor crystal substrate, a method of manufacturing a semiconductor device, a semiconductor crystal substrate manufacturing method and a semiconductor device

PROBLEM TO BE SOLVED: To provide a semiconductor crystal substrate for forming a semiconductor device with suppressed Fe diffusion to an electron transit layer while successfully maintaining crystallinity of the electron transit layer.SOLUTION: A semiconductor crystal substrate comprises: a first buffer layer 21 formed of a nitride semiconductor on a substrate 10; a second buffer layer 22 formed on the first buffer layer 21; a first semiconductor layer 31 formed on the second buffer layer 22; and a second semiconductor layer 32 formed on the first semiconductor layer 31. In the first buffer layer 21, a concentration of Fe is higher than a concentration of C. In the second buffer layer 22, a concentration of C is higher than a concentration of Fe.SELECTED DRAWING: Figure 3