n-型（100）矽單晶巨孔洞之電化學研究

Electrochemical Study in the Formation of Macropores on n-type Si(100)

本研究主要探討n-型（100）矽單晶於含酒精氫氟溶液中之光電化學行為。研究方法首先採用直流電陽極動態極化法，探討照光強度，氫氟酸濃度等參數對n-型（100）矽單晶的陽極極化曲線的影響。研究結果顯示：在n-型（100）矽單晶背面以鹵素燈照射，及提高蝕刻液中氫氟酸濃度，均會增進電化學蝕刻速率。當氫氟酸濃度與照光強度固定下，在蝕刻溶液中添加酒精會影響矽單晶之陽極腐蝕行為。經由陽極動態極化曲線選取特定電位，針對n-型（100）單晶矽於照光環境（50W），在含不同濃度酒精之2M氫氟酸中，同時進行定電位蝕刻與交流阻抗分析，並以掃瞄式電子顯微鏡觀察其蝕孔之表面型態，結果顯示添加酒精將有助於蝕孔更具平滑性。

The photo-electrochemical behavior of n-type Si (100) in an ethanolic hydrofluoric acid (HF) has been investigated in this work. Dc-potentiodynamic polarization of the silicon, whose backside was lighted with a halogen lamp, was conducted in the HF solution containing ethanol or not. The voltammogram demonstrated that the anodic dissolution rate of the silicon in the HF solution was accelerated by illumination. The dissolution rate was accelerated when the power of illumination intensified and the HF concentration increased. Addition of ethanol into the HF solution resulted in electro-polishing inside the pits. Potentiostatic dissolution of the silicon, lighted with a halogen lamp (50 W ), was conducted in 2 M HF solution containing various amounts of ethanol at potentials selected from the anodic polarization diagram. Electrochemical impedance spectroscopy was also carried out in the same condition. The surface morphology on the etched silicon under various conditions was examined by scanning electron microscopy (SEM).