Manufacture of semiconductor device

TLDR: In this article, the authors proposed to prevent the emitting intensity of photoluminescence from receiving any adverse effect by forming porous silicon by subjecting single-crystal silicon to an anode formation treatment and removing an oxide film formed on the surface of the porous silicon with diluted hydrofluoric acid.

Abstract: PURPOSE:To prevent the emitting intensity of photoluminescence from receiving any adverse effect by forming porous silicon by subjecting single-crystal silicon to an anode formation treatment and removing an oxide film formed on the surface of the porous silicon with diluted hydrofluoric acid CONSTITUTION:After an aluminum electrode board 2 is put on the rear surface of a p-type single-crystal silicon substrate 1, the substrate 1 and board 2 are coated with wax 3 so that the front surface of the substrate 1 can be exposed The substrate 1 and board 2 are dipped in 25% hydrofluoric acid 4 and a platinum electrode 5 is also dipped in the acid 4 at the opposite position of the substrate 1 Then the surface of the substrate 1 is subjected to an anode formation treatment by using the substrate 1 as an anode and electrode 5 as a cathode Namely, the silicon of the substrate 1 is oxidized to SiO2 by active oxygen generated on the surface of the substrate 1 and the SiO2 dissolves in the acid 4 As a result, columnar porous silicon having a pore diameter of about 50Angstrom is formed on the surface of the substrate Then the substrate 1 coated with the porous silicon is dipped in 5% hydrofluoric acid for five minutes and a surface oxide film is removed Therefore, the emitting intensity of photoluminescence can be improved