本研究主要探討n-型（100）矽單晶於含酒精氫氟酸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，以決定實驗參數。研究結果顯示：在n-型（100）矽單晶背面照光，及提高蝕刻液中氫氟酸濃度，會促進電化學蝕刻速率之增加。 實驗結果顯示，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，20000Lx），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。 此外，利用開路電位量測與交流阻抗分析，探討照光強度，氫氟酸與酒精濃度等參數對n-型（100）單晶矽的介面反應，結果顯示照光與添加酒精將有利介面電荷轉移，然而提高氫氟酸濃度其反應不易進行。 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, illuminated by a halogen lamp from its backside, 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 the illumination. The etching rate was faster when the illumination power is intensified, and the HF concentration increased. The effect of ethanol addition in the HF solution was also of interest. The electrochemical behavior of the silicon depicted that the presence of ethanol in the HF solution resulted in electro-polish inside the etching pits. Potentiostatic etching of the silicon, illuminated with a halogen lamp (50 W and 20,000 Lx), was conducted in 2 M HF solution containing a variety of ethanol at certain 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), and the surface roughness was evaluated by atomic force microscopy (AFM). The open circuit potential (OCP) for the silicon, illuminated with lamp and immersed in various solutions, was measured. Further checking the results from EIS at OCP, one concluded that illumination and ethanol-addition are advantageous to preparation of macro-porous silicon.
