| abstract |
The present invention eliminates the possibility that the vicinity of the surface of a semiconductor substrate is damaged by plasma ions. An etching container in which an etchant is stored, a support 204 to which a structure to be etched of a group III nitride semiconductor is fixed, an cathode provided in the etching container, a cathode, An ammeter 210 connected in series with the extraction electrode 206 provided in the structure to be etched 112, an ultrahigh pressure mercury lamp, and an ultrahigh pressure mercury lamp, and has a wavelength shorter than 365 nm and 300 nm to And a filter for irradiating the structure to be etched with light longer than a predetermined wavelength of 350 nm. [Selection] Figure 4 |