MECHANOCHEMICAL OXIDATION OF SILICON AND SELECTIVITY OF OXIDE SUPERFICIAL LAYER DISSOLUTION IN AQUEOUS-SOLUTIONS OF HF AND KOH

Mechanochemical oxidation of silicon and selectivity of oxide layer di ssolution in diluted solutions of KF and KOH were investigated. Energy -intensive grinding of Si is accompanied by changes in state and compo sition of superficial layers and by significant decrease in crystallin ity. The effect of the polarity of liquid grinding environment on the amorphisation is not significant. The permittivity of liquid influence s oxidation of silicon and surface concentration of damage centers. Th e porous oxide shell covering the ground particles controls the adsorp tion behaviour of Si and consequently its dissolution in diluted solut ions of HF and KOH. Stimulating or inhibiting effect of mechanically i nduced pre-oxidation depends upon the mechanism of dissolution. While selective dissolution of oxide in KF is facilitated by the pre-oxidati on, the direct dissolution of silicon in alkaline solvents is inhibite d by oxide surface layer.