The Effect of Negative Substrate Bias on the Strain Prosperities of ZnO Films Deposited by PFCVAD

Abstract

Keeping deposition temperature and oxygen pressure constant at 300°C and 4.0×10-2Pa, respectively, deposition of ZnO thin films with c-axis oriented (002) hexagonal wurtzite crystal structure was achieved by pulsed filtered cathodic vacuum arc deposition (PFCVAD) system at various negative substrate bias on Si(100). The surface morphology was characterized using AFM, and crystallographic structure was studied by means of X-ray diffraction. Based on the biaxial strain model, Strain properties of the ZnO films were investigated by calculation from XRD data. The calculated results revealed that the as-deposited ZnO films exhibited only tensile stress and the tensile stress increased with the elevation of the negative substrate bias. Occurrence of the tensile stress is suggested to be the result of relatively high deposition temperature and the improved deposition rate by elevating the negative substrate bias. It provides a potential method to control the intrinsic stress in the ZnO films by modulation of deposition temperature and the negative substrate bias of PFCVAD system.