本論文主要探討黑晶片的蝕刻條件來達到低反射率，同時探討清洗方式對黑晶片的影響來達到低反射率且高載子生命週期的黑晶片。以我們蝕刻液的配方，我們發現在p-type FZ晶片上成長黑晶片結構時，反射率不會隨著蝕刻時間增加而增加，而是在135秒會有最低點約為4% (600nm波段)。接著我們進行清洗條件的最佳化發現利用氨水的清洗方式會造成過度的蝕刻，對黑晶片奈米孔洞的結構會造成嚴重破壞，鹽酸和硫酸對黑晶片的結構破壞較不嚴重，而且硫酸的清洗效果相較於其他方法好，載子生命週期可以達到950μs (以碘液鈍化的情況下)，同時反射率約為5% (600nm波段)。最後我們實際應用在經KOH蝕刻成金字塔結構晶片上，載子生命週期可以達到684μs並且有5% (600nm波段)反射率，和只有KOH蝕刻成金字塔結構晶片相比反射率降低了8%，載子生命週期回復了61%。

We optimized the condition in metal-assisted chemical etching in order to obtain the lowest reflection of our black silicon. Meanwhile, we also optimized several cleaning methods to obtain black silicon which has low reflection but high minority carrier lifetime. We found that in our condition, reflection won’t get lower as the etching time stays longer. Our black silicon has reflection 4% at 600nm, while the etching time is 135 second. In cleaning part we found that ammonia is not suitable for cleaning black silicon because it causes too much etching to the wafer. Hydrochloric acid and sulphuric acid cause less etching to black silicon. Sulphuric acid has better cleaning ability than the others. We obtained 950μs minority carrier lifetime on our best black silicon and its reflection is 5% (at 600nm). Eventually we apply to KOH textured silicon wafer. We obtained 684μs minority carrier lifetime and reflection 5% at 600nm. Compare with wafers only textured by KOH, we lowered the reflection by 8% and the minority carrier lifetime recovered by 61%.

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