| 摘要 |
The objective of the present invention is to achieve a nitride semiconductor multilayer film reflector which has been made to exhibit low electrical resistance. In a nitride semiconductor multilayer film reflector: an Al composition ratio of first semiconductor layers (104) is higher than an Al composition ratio of second semiconductor layers (106); in between a first semiconductor layer (104) and a second semiconductor layer (106), a first compositionally graded layer (105) is interposed on the group III element surface-side of the first semiconductor layer (104), said first compositionally graded layer having been adjusted so that an Al composition ratio becomes lower as the second semiconductor layer (106) is approached, and a second compositionally graded layer (103) is interposed on the nitride surface-side of the first semiconductor layer (104), said second compositionally graded layer having been adjusted so that an Al composition ratio becomes lower as the second semiconductor layer (106) is approached; energy levels with respect to electrons of the lower ends of the conduction bands of the first semiconductor layers (104), the second semiconductor layers (106), the first compositionally graded layers (105), and the second compositionally graded layers (103) are continuous without offset; and n-type impurity concentration in the first compositionally graded layers (105) is greater than or equal to 5 × 1019 cm-3. |
