The Transactions of the Korean Institute of Electrical Engineers C (대한전기학회논문지:전기물성ㆍ응용부문C)

The Korean Institute of Electrical Engineers (대한전기학회)
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Deposition of ZnO Thin Films by RF Magnetron Sputtering and Cu-doping Effects

RF 마그네트론 스퍼터링에 의한 ZnO박막의 증착 및 구리 도우핑 효과

  • Lee, Jin-Bok (Dept. of Electrical Engineering, Hanyang University) ;
  • Lee, Hye-Jeong (Dept. of Electronic Electrical Control Instrumentation Engineering, Hanyang University) ;
  • Seo, Su-Hyeong (Deparment of Physics and Center for Electronic Materials and Components) ;
  • Park, Jin-Seok (Dept. of Electronic Computer Engineering, Engineering Collage, Hanyang University)
  • 이진복 (한양대 전기공학과) ;
  • 이혜정 (한양대 전자전기제어계측공학과) ;
  • 서수형 (한양대 전자재료 및 부품 연구센터 Post-Doc) ;
  • 박진석 (한양대 전자컴퓨터학부)
  • Published : 2000.12.01
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Abstract

Thin films of ZnO are deposited by using an RF magnetron sputtering with varying the substrate temperature(RT~39$0^{\circ}C$) and RF power(50~250W). Cu-doped ZnO(denoted by ZnO:Cu) films have also been prepared by co-spputtering of a ZnO target on which some Cu-chips are attached. Different substrate materials, such as Si, $SiO_{2}/Si$, sapphire, DLC/Si, and poly-diamond/Si, are employed to compare the c-axial growth features of deposited ZnO films. Texture coefficient(TC) values for the (002)-preferential growth are estimated from the XRD spectra of deposited films. Optimal ranges of RF powers and substrate temperatures for obtaining high TC values are determined. Effects of Cu-doping conditions, such as relative Cu-chip sputtering areas, $O_{2}/(Ar+O_{2})$ mixing ratios, and reactor pressures, on TC values, electrical resistivities, and relative Cu-compositions of deposited ZnO:Cu films have been systematically investigated. XPS study shows that the relative densities of metallic $Cu(Cu^{0})$ atoms and $CuO(Cu^{2+})$-phases within deposited films may play an important role of determining their electrical resistivities. It should be noted from the experimental results that highly resistive(> $10^{10}{\Omega}cm$ ZnO films with high TC values(> 80%) can be achieved by Cu-doping. SAW devices with ZnO(or Zn):Cu)/IDT/$SiO_{2}$/Si configuration are also fabricated to estimate the effective electric-mechanical coupling coefficient($k_{eff}^{2}$) and the insertion loss. It is observed that the devices using the Cu-doped ZnO films have a higher $k_{eff}^{2}$ and a lower insertion loss, compared with those using the undoped films.

Keywords

References

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