磷化銦及磷化銦鎵的甲烷與氫氣活性離子蝕刻

Abstract

本論文要旨在研究磷化銦及磷化銦鎵兩種化合物半導體在甲烷與氫氣混合 電漿中的活性離子蝕刻，所研究的相關變數包括蝕刻的時間、功率密度、 甲烷與氫氣混合體積比、壓力大小以及氣體的總流率等等。其中，甲烷與 氫氣的混合體積比是較為重要的參數，因為它影響晶片的蝕刻速率、聚合 物的沉積速率、表面的化學計量及非等向性蝕刻等結果較其它參數更顯著 。當甲烷與氫氣的混合體積比為 1 : 3 時，磷化銦及磷化銦鎵的蝕刻速 率最大。在一般狀況下，磷化銦的蝕刻速率約為磷化銦鎵的 3 ~ 6 倍， 我們所得到磷化銦及磷化銦鎵的最大蝕刻速率分別為每分鐘 1450 及 400 埃。最後我們分別應用掃瞄式電子顯微鏡、二次離子質譜儀、歐傑電 子能譜儀及X射線光電子能譜儀來檢查磊晶層厚度並分析各晶片在蝕刻後 的表面狀況。 In this thesis, we report the reactive ion etching of InGaP and InP (including undoped, p and n+ type ) in CH4/H2 mixtures. The etch rate was measured as a function of etch time, rf power density, methane fraction,chamber pressure, and total flow rate. The relative fraction of methane and hydrogen is the most important parameter that controls the etch rate, polymer deposition rate, surface stoichiometry, and anisotropy. Both InP and InGaP have the maximum etch rate at CH4/H2 = 1 : 3 ( CH4 % = 25 % ) when the other parameters were kept constant. The InP etch rate is found to increase nearly linearly with rf power density over the range studied. The etch rates of InP and InGaP, up to 145 and 40 nm/min, are obtained respectively. Generally, the trend of etch rate is : InP ( n = 5.9 * 1015 cm-3 ) > p-InP ( n = 5 * 1018 cm-3, Zn doped ) ~ n+-InP ( n = 3 * 1018 cm-3, Sn doped ) >> InGaP ( n = 1 * 1018 cm-3, Si doped ). The average etch rate of InP is about 3 * 6 times faster than that of InGaP. There are many measurements, such as SEM, SIMS, AES, and XPS have been made to check the thickness of the epitaxial layer, and analyze the surface morphology and chemistry after RIE.