Interdigital variable capacitance diode and preparation method thereof

The invention provides an interdigital variable capacitance diode and a preparation method thereof, and the preparation method comprises the steps: preparing a first interdigital P-type ohmic contact electrode in a first preset region on a P-type ohmic contact layer; the P-type ohmic contact layer provided with the first interdigital P-type ohmic contact electrode is etched, so that an included angle is formed between the side wall of an etching table surface obtained after etching and the N-type ohmic contact layer; respectively preparing a second interdigital N-type ohmic contact electrode and a third interdigital N-type ohmic contact electrode in a second preset area and a third preset area on the N-type ohmic contact layer; etching the N-type ohmic contact layer provided with the second interdigital N-type ohmic contact electrode, the third interdigital N-type ohmic contact electrode and the first interdigital P-type ohmic contact electrode until the semi-insulating substrate is exposed; and growing a met