CPC C30B 29/42 (2013.01) [C30B 33/02 (2013.01); G01N 23/2273 (2013.01)] | 11 Claims |
1. A gallium arsenide single crystal substrate having a main surface, wherein
a ratio of a number of As atoms existing as diarsenic trioxide to a number of As atoms existing as diarsenic pentoxide is greater than or equal to 2 when the main surface is measured by X-ray photoelectron spectroscopy, in which an X-ray having an energy of 150 eV is used and a take-off angle of a photoelectron is set to 5°, and
arithmetic average roughness Ra of the main surface is less than or equal to 0.3 nm.
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