PS Formation and Electrochemical Polishing

Examination of the sample surfaces that are anodized at different potentials indicates that the potential corresponding to the maximnm slope of the i-V cnrve is the upper limit for formation of a uniform PS layer. At potentials between the maximum slope and current peak, the porous layer may still form but the surface coverage is not uniform. Thus, the anodic behavior is characterized by three regions PS formation, transition, and eleclropolishing.  

FIGURE 8.5. A plot of critical current densities as a function of HF concentration. Solid line is the peak current density dashed line is the current density at the maximum slope shown in Fig. 5.3. After Zhang et al (Reproduced by permission of The Electrochemical Society, Inc.) 

FIGURE 8.6. The i-V behavior of p-Si and n-Si (scan rate 0.5 V/s) illuminated with a 300mW/cm quartz halogen lamp in 2 M HE + 0.25 M TBAP in MeCN and in 2 M HF + 1M NH4F in H2O. After Propst and Kohl. (Reproduced by permission of The Electrochemical Society, Inc.) 

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