506
P. Joshi et al.
Fig. 9 a–c Effect of oxygen partial pressure on hexagonal wurtzite ZnO with substrate bonding
structure in presence of a low, b moderate and c high oxygen contents
growth of ZnO lattice. Therefore, change in crystal lattice parameters generates inplane stress between ZnO and substrate atoms. Figure 9b represents ZnO crystalline
stress relaxed growth in presence of moderate oxygen partial pressure (~40%). This
moderate oxygen pressure provides perfect hexagonal wurtzite growth and proper
Zn/O stoichiometry. At higher oxygen partial pressure (>40%), excessive oxygen
might be incorporated in the ZnO lattice and distort the crystal structures as shown
in Fig. 9c.
All polycrystalline single-phase ZnO films have shown oxygen partial pressure
dependent physical properties and require precise control of processing parameters
to obtain high-quality ZnO thin films.
4 Conclusion
Stress relaxed and highly c-axis oriented single-phase ZnO thin film was deposited
at room temperature using reactive sputtering process. The crystalline structure and
mechanical stress of vacuum-deposited films are very sensitive to deposition conditions. The oxygen flow in the chamber (30–60%) was varied to tune the physical
properties. It was found that stress varies in −0.06 × 10
9 dyne/cm
2 to −2.27 × 10
9
P. Joshi et al.
Fig. 9 a–c Effect of oxygen partial pressure on hexagonal wurtzite ZnO with substrate bonding
structure in presence of a low, b moderate and c high oxygen contents
growth of ZnO lattice. Therefore, change in crystal lattice parameters generates inplane stress between ZnO and substrate atoms. Figure 9b represents ZnO crystalline
stress relaxed growth in presence of moderate oxygen partial pressure (~40%). This
moderate oxygen pressure provides perfect hexagonal wurtzite growth and proper
Zn/O stoichiometry. At higher oxygen partial pressure (>40%), excessive oxygen
might be incorporated in the ZnO lattice and distort the crystal structures as shown
in Fig. 9c.
All polycrystalline single-phase ZnO films have shown oxygen partial pressure
dependent physical properties and require precise control of processing parameters
to obtain high-quality ZnO thin films.
4 Conclusion
Stress relaxed and highly c-axis oriented single-phase ZnO thin film was deposited
at room temperature using reactive sputtering process. The crystalline structure and
mechanical stress of vacuum-deposited films are very sensitive to deposition conditions. The oxygen flow in the chamber (30–60%) was varied to tune the physical
properties. It was found that stress varies in −0.06 × 10
9 dyne/cm
2 to −2.27 × 10
9