Structural and Electrically Conductive Properties of Plasma-Enhanced Chemical-Vapor-Deposited High-Resistivity Zn-Doped β-Ga2O3 Thin Films

A method was developed for plasma-enhanced chemical vapor deposition of β-Ga₂O₃:Zn thin films with the possibility of pre-purifying precursors. The structural and electrically conductive properties of β-Ga₂O₃:Zn thin films were studied. Increasing the temperature of the Zn source (<i>T</i>_Zn) to 220 °C led to the formation of Ga₂O₃ films with a Zn concentration of 4 at.%, at <i>T</i>_Zn = 230 °C [Zn] = 6 at.% and at 235 °C. [Zn] = 8 at.% At <i>T</i>_Zn = 23 °C, the films corresponded to the β-Ga₂O₃ phase and were single-crystalline with a surface orientation of (-201). As <i>T</i>_Zn increased, the polycrystalline structure of β-Ga₂O₃ films with a predominant orientation of (111) was formed. The introduction of Zn led to the formation of a more developed microrelief of the surface. Raman spectroscopy showed that a small concentration of impurity atoms tended to replace gallium atoms in the oxide lattice, which was also confirmed by the Hall measurements. The concentration of charge carriers upon the introduction of Zn, which is a deep acceptor, decreased by 2-3 orders of magnitude, which mainly determined the decrease in the films' resistivity. The resulting thin films were promising for the development of high-resistivity areas of β-Ga₂O₃-based devices.