| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide epitaxial substrates for electronic devices that have both reduced transverse leakage current and transverse pressure resistance characteristics, and which can improve longitudinal pressure resistance. <P>SOLUTION: The epitaxial substrates are provided with a main laminate 4 formed by epitaxially growing group III nitride layers on a buffer 3 on an Si substrate 1, and having a channel layer 4a and an electron supply layer 4b. The buffer comprises an initial growth layer 5 that contacts the Si substrate 1 and a superlattice laminate 6 having a superlattice structure on the initial growth layer. The initial growth layer is composed of AIN material. The superlattice laminate is made by alternately laminating a first layer 6a comprising a B<SB>a1</SB>Al<SB>b1</SB>Ga<SB>c1</SB>In<SB>d1</SB>N material with a second layer 6b comprising a B<SB>a2</SB>Al<SB>b2</SB>Ga<SB>c2</SB>In<SB>d2</SB>N material having a different band gap from the first layer. The superlattice laminate and the buffer side portion of the channel layer constituting the main laminate are characterized in having C concentrations of 1×10<SP>18</SP>/cm<SP>3</SP>or greater, and the electron supply layer side portion of the channel layer is characterized in having a C concentration of 4×10<SP>16</SP>/cm<SP>3</SP>or less. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
