Effect of the duration of electrochemical anodization on the microhardness of macroporous silicon

The dependence of the microhardness H of macroporous silicon layers formed on the duration t _an of electrochemical anodization at a constant current density of J = 20 mA/cm² is studied. It is shown that the nonlinear run of the dependence H(t _an) is due to the influence exerted on the microhardness not only by the surface density of pores, but also by the single-crystal base at L < 10h, where L and h are the thickness of the porous layer and the depth of indenter penetration, respectively.