| 摘要 |
PROBLEM TO BE SOLVED: To reduce a patterning frequency and to obtain a new lattice pattern for detecting an infrared ray with a short wavelength by equipping a diffraction pattern that is formed on a light absorption layer, includes a curved shape on a plane, and has a single-stage, step-shaped groove on a section. SOLUTION: Resist is applied onto a second 2n-type gallium arsenic (GaAs) layer 14, which is exposed and developed for forming a resist pattern 15. The resist pattern 15 is a diffraction pattern including a curve and is provided with, for example, an opening, flat shape where a pattern with a first elliptic curve being smaller than a second elliptic curve in the second elliptic curve is divided into four portions. After that, a part that is not covered with the resist pattern 15 out of the second 2n-type GaAs layer 14 is etched and one portion of a flat shape that is partially an elliptic curve is included on the upper surface of the second 2n-type GaAs layer 14, and a groove 14a with a step whose sectional shape is in one step is formed. After that, the resist pattern 15 is eliminated by a solvent, thus forming a new diffraction pattern with the groove 14a on the upper surface of the second 2n-type GaAs layer 14.
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