RF 마그네트론 스퍼터링 방법을 사용해 증착된 Al이 도핑 된 ZnO 박막의 H2/ (Ar + H2) 가스 비율에 따른 특성
The properties of Al-doped ZnO films deposited with RF magnetron sputtering system in various H2/(Ar + H2) gas ratios
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Al2O3 2 wt%가 도핑 된 ZnO(AZO) 타겟으로RF 스퍼터링 장비를 사용하여 H2/(Ar + H2) 가스 비율에 따른 AZO 박막을 증착 후, 이들 박막의 특성을 조사하였다. AZO 박막은 200oC, 2 × 10−2 공정조건에서 H2/(Ar + H2) 가스 비율을 변화시키면서 증착하였다. AZO박막증착 중 수소가스의 첨가는 박막의 특성에 영향을 미쳤다. H2/(Ar + H2) 가스 비율이 2.5 %일 때 비 저항(~9.21 × 10−4 Ωcm)과 전자 이동도(~17.8 cm2/Vs)는 각각 최소값과 최대값을 나타내었다. H2/(Ar + H2) 가스 비율이 2.5 % 이상일 때는 H2/(Ar + H2) 가스 비율이 증가할수록 비저항은 점차로 증가하였고 전자 이동도는 점차적으로 감소하였다. 전자 운반자 농도는 H2/(Ar + H2) 가스 비율이 증가함에 따라 0 %에서 7.5 %까지 점차로 증가하였다. H2/(Ar + H2)가스 비율에 따라 증착된 박막의 가시광선 파장 범위에서 평균 광 투과도는 90 % 이상이었고 성장방향은 [002]이었다.
Abstract
The properties of Al-doped ZnO (AZO) films were investigated as a function of H2/(Ar + H2) gas ratio using an AZO (2 wt% Al2O3) ceramic target in a radio frequency (RF) magnetron sputtering system. The deposition process was done at 200oC and in 2 × 10−2 Torr working pressure and with various ratios of H2/(Ar + H2) gas. During the AZO film deposition process, partial H2 gas affected the AZO film characteristics. The electron resistivity (~9.21 × 10−4 Ωcm) was lowest and mobility (~17.8 cm2/Vs) was highest in AZO films when the H2/(Ar + H2) gas ratio was 2.5 %. When the H2/(Ar + H2) gas ratio was increased above 2.5 %, the electron resistivity increased and mobility decreased with increasing H2/(Ar + H2) gas ratio in AZO films. The carrier concentration increased with increasing H2/(Ar + H2) gas ratio from 0 % to 7.5 %. This phenomenon was explained by reaction of hydrogen and oxygen and additional formation of oxygen vacancy. The average optical transmission in the visible light wavelength region over 90 % and an orientation of the deposition was [002] orientation for AZO films grown with all H2/(Ar + H2) gas ratios.
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