(華中科技大學(xué) 模具技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室， 武漢 430074)
摘 要: 選擇In2O3與SnO2質(zhì)量比1∶1的靶材為濺射源，采用磁控濺射法沉積了ITO薄膜， 討論了濺射氬氣壓強(qiáng)、 氧流量、 基體溫度對(duì)薄膜透射率和方阻的影響， 深入分析了其機(jī)理。研究結(jié)果表明： 濺射時(shí)采用低Ar壓強(qiáng)更有利于降低ITO薄膜的電阻率，并確定最佳氬氣壓強(qiáng)為0.2 Pa， 厚度為120 nm的ITO薄膜在可見(jiàn)光區(qū)的透過(guò)率可達(dá)到90%； 氧流量能明顯改變薄膜的性能， 隨著氧流量從0增加10 L/min(標(biāo)準(zhǔn)狀態(tài)下，下同)， 載流子濃度(N)則由3.2×1020降低到1.2×1019/cm3， N值的變化與ITO薄膜光學(xué)禁帶寬度(Eg)的變化密切相關(guān)。 振子模型與實(shí)驗(yàn)結(jié)果吻合， 并確定了ITO薄膜的等離子波長(zhǎng)(λp＝1 510 nm）。 薄膜隨方阻減小表現(xiàn)出明顯的“B-M”效應(yīng)。 通過(guò)線性外推， 建立了直接躍遷的(αE)2模型， 并確定了薄膜的Eg值(3.5~3.86 eV)。
關(guān)鍵字: ITO薄膜； 磁控濺射； 氧流量； “B-M”效應(yīng)
thin films deposited by magnetic sputtering
（ State Key Laboratory of Die and Mould Technology,
Huazhong University of Science and Technology， Wuhan 430074, China）
Abstract: The ITO thin films were prepared by radio frequency magnetic sputtering using a ceramic target with mass ratio of In2O3 to SnO2 1∶1. The experiment parameters such as Ar gas pressure (p(Ar)), oxygen flow rate (f(O2)) and substrate temperature (ts) all have important influence on the transmittance and square resistivity of the thin films. The semiconductor mechanisms of ITO films were studied. The results show that lower p(Ar) can reduce Rs, the optimal p(Ar) of about 0.2 Pa was determined. The transmittance of 120 nm thick ITO thin films in visible light range is about 90%. The ITO properties can be changed obviously by f(O2), the carrier concentration decrease from 3.2×1020 to 1.2×1019/cm3 when f(O2) increases from 0 to 10 L/min(standard state), which is related to optical forbidden band Eg. And the oscillator model is accorded with the experimental results, the plasma wavelength of ITO films is up to 1 510 nm.The thin films shows obvious “Burstin-Moss” effect due to a decrease in Rs. The direct transition model of (αE)2 versus photon energy Eg was established and a band gap energy Eg was obtained by linear extrapolation.
Key words: ITO thin films；magnetic sputtering；oxygen flow rate； “Burstin-Moss” effect
