本研究為使用氫氟酸:酒精比例1:1在兩組電流下超低溫電化學蝕刻P型重參矽晶圓，觀察低溫對表面微結構與表面奈米晶體尺寸的影響。並使用場發射掃描式電子顯微鏡(SEM)、穿透式電子顯微鏡(TEM)、光致發光光譜儀(PL)做進一步分析。低溫下因水的解離率與反應速率降低導致矽之氟蝕刻與氫氧基蝕刻被降至很低，厄弗法則解釋蝕刻液的表面張力增加導致應力腐蝕，重參P型矽卻不會因溫度降低改變電導率，三種原因導致蝕刻出的矽晶表面多孔結構相較於常溫孔洞更淺並趨於球型，奈米晶體也因尺寸縮小致使光致發光光譜發生藍移現象。 相較於常見的化學氣相沉積法與電漿沉積法，低溫電化學蝕刻法有設備相對簡單、成本低廉等的優點，較適合大規模應用於生物標記與防偽辨識。 ;We adopt the cryogenic electrochemical method to etch heavily-doped p-type silicon wafer under two sets of current with the etchant that mix hydrofluoric acid and ethanol with 1:1 volume percentage, then observe the influence of low temperature to surface microstructure and size of surface nanocrystal using field-emission scanning electron microscope(SEM)、transmission electron microscope(TEM) and photoluminescence(PL). There are three reasons which make the surface porous structure more shallow and more spherical in deep cold environment: 1. The reaction rate and dissociation rate decrease lead to a low etch rate. 2. The surface tension increase lead to stress corrosion. 3. The conductivity of heavily-doped silicon remains almost the same in the cryogenic environment. The low temperature also causes blue shift in the PL, which can be attributed to the size decrease of nanoparticles of silicon. In comparison with Chemical Vapor Deposition(CVD) and Plasma Synthesis, the cryogenic electrochemical etching has the advantage of simple equipment and inexpensive cost. That makes it suitable for biomarker and banknotes anti-counterfeiting.
