利用脈衝雷射濺鍍氧化鋅薄膜之製成與特性研究

Abstract

藉由改變不同的基板溫度跟不同的氧壓，使用准分子雷射(波長＝248nm)雷射功率密度1J/cm2跟重複頻率10Hz濺鍍15分鐘成功的將純度99.99%的氧化鋅靶材濺鍍在氧化鋁（0001）上成長出有高的c軸取向的氧化鋅薄膜。由X光繞射光譜的氧化鋅的（002）峰在2θ=34.614o 的位置有0.23o的半高寬，我們發現氧化鋅在氧化鋁基板溫度(Ts)為650℃，通入氧壓為1.0x10-3mbar時，會有比較好的晶相。在可見光穿透光譜發現氧化鋅有3.37eV的能隙，薄膜厚度約為140nm；並發現在Ts＝450℃時，有最大的穿透率83.0%。在電性上，我們發現在較低的基板溫度下成長的氧化鋅薄膜有較低的阻值。由X光繞射光譜跟拉曼光譜知道氧化鋁(0001)基板對氧化鋅薄膜的成長來說比矽晶(100)及石英玻璃來得好。

Highly c-axis-oriented ZnO films have been successfully fabricated on sapphire (0001) by a KrF-excimer laser (wavelength = 248 nm) deposition from a stoichiometrical ZnO (99.99%) target under various substrate temperatures and oxygen pressures with laser fluence of 1 J/cm2 and 10 Hz-repetition rate for 15 min. We found the best sample grown at the substrate temperature(Ts) of 650℃ and of 1x10-3 mbar O2 pressure shows the full width at half maximum (FWHM) of the (0002) peak of the x-ray diffraction pattern located at 2θ=34.614o to be 0.23o. From the spectral transmittance, we determined the energy bandgap of the films to be 3.37 eV and the film thickness around 140 nm. Highly transmittance is equal to 83% at Ts=450℃. The films have the lower resistivity at the lower substrate temperature. By obtaining x-ray diffraction spectra and Raman spectra, the sapphire(0001) substrate of the ZnO films is better than si(100) and quartz glass.