| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nitride semiconductor substrate which can achieve both a higher threshold voltage and a reduced current collapse and is suitable for a normally-off type high-voltage device; and a method of manufacturing the same. <P>SOLUTION: A nitride semiconductor substrate 10 comprises: a substrate 1; a buffer layer 2 that is formed on one main surface of the substrate 1; an intermediate layer 3 that is formed on the buffer layer 2; an electron transit layer 4 that is formed on the intermediate layer 3; and an electron supply layer 5 that is formed on the electron transit layer 4. In the substrate 10, Al<SB POS="POST">x</SB>Ga<SB POS="POST">1-x</SB>N(0.05≤x≤0.24), which has a thickness of at least 200 nm and 1500 nm or less and a carbon concentration of at least 5×10<SP POS="POST">16</SP>atoms/cm<SP POS="POST">3</SP>and 1×10<SP POS="POST">18</SP>atoms/cm<SP POS="POST">3</SP>or less, is used as the intermediate layer 3; and Al<SB POS="POST">y</SB>Ga<SB POS="POST">1-y</SB>N(0≤y≤0.04), which has a thickness of at least 5nm and 200 nm or less, is used as the electron transit layer 4. <P>COPYRIGHT: (C)2013,JPO&INPIT |
