| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively provide a compound semiconductor substrate suppressed in occurrence of a crack and warpage, and suitable for a normally-off type high-breakdown-voltage device. SOLUTION: This compound semiconductor substrate includes a structure wherein a multilayer buffer layer 2 in which Al<SB>x</SB>Ga<SB>1-x</SB>N single-crystal layers (0.6≤x≤1.0) 21 containing carbon of 1×10<SP>18</SP>to 1×10<SP>21</SP>atoms/cm<SP>3</SP>and Al<SB>y</SB>Ga<SB>1-y</SB>N single-crystal layers (0.1≤y≤0.5) 22 containing carbon of 1×10<SP>17</SP>to 1×10<SP>21</SP>atoms/cm<SP>3</SP>are alternately and repeatedly stacked in order, and a nitride active layer 3 comprising an electron transit layer 31 having a carbon content concentration≤5×10<SP>17</SP>atoms/cm<SP>3</SP>and an electron supply layer 32 are sequentially deposited on a Si single-crystal substrate 1, wherein both the carbon content concentration of the Al<SB>x</SB>Ga<SB>1-x</SB>N single-crystal layers 21 and that of the Al<SB>y</SB>Ga<SB>1-y</SB>N single-crystal layers 22 respectively decrease from the substrate 1 side towards an active layer 3 side. COPYRIGHT: (C)2011,JPO&INPIT
|
