n^+-Si在HF溶液中的阳极极化行为和阻抗谱

n^+-Si在0.25～1.0%HF溶液中无光照和光照下的伏安曲线均明显地分为三段:在低极化下呈线性关系, 对应于硅的阳极溶解, 形成多孔硅层(PSL); 在中间电位区, 电极部分表面为硅氧化物所覆盖, 阳极溶解和非均匀电抛光过程同时进行; 在高极化区, 全部表面为硅氧化物所覆盖, 发生均匀的电抛光过程。在上述三个区域中由交流阻抗测得的特征电容环和电感应环的变化, 揭示了由单一阳极溶解逐渐转变为均匀抛光过程的一些细节, 定性地说明了n^+-Si上进行的竞争性反应的速率是随电位而改变, 并受光照影响。

Anodic polarization behavior and impedance response of n^+-Si in hydrofluoric acid solution

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.