P-TYPE AND N-TYPE SILICON ELECTROCHEMICAL PROPERTIES IN DILUTE HYDROFLUORIC-ACID SOLUTIONS

After a systematic study of the factors influencing the electrochemica l characteristics of the silicon/HF solution junction, we have obtaine d reproducible and reliable values of the electrochemical kinetic para meters of the interface. One of the features of this system is that th e corrosion reaction on anodic and cathodic sites is equivalent to two redox reactions, one at the energy level of the conduction band, the other at the level of the valence band. Then, we supported the assumpt ion that the junction with Si can be treated by the electrochemical mo del. Data have been obtained using n- and p-type silicon with differen t doping levels, in contact with deoxygenated or oxygen-saturated 5% H F aqueous solution, in the dark and under illumination. The electroche mical reaction kinetics are expressed as a corrosion rate in atom cm(- 2) s(-1) for different Si substrates.