The voltammetric curves of heavily doped n-Si(n^+-Si) closely related to the concentration of HF solution and the irradiation were investigated. There are generally three regions on each i-φ curve: porous silicon formation at low potentials, electropolishing at high potentials and a transition region located in between. The corresponding complex plane impedance plots of n^+-Si at above three potential regions is dependent on the potential and light illumintion. The influence of the illumination on the impendance were measured and discussed.

Key words: POLISHING, SEMICONDUCTOR, PHOTO-ELECTROCHEMISTRY, POROUS SILICON, ANODIC POLARIZATION