Kesheng Guo

Yttrium oxide (Y₂O₃) films have been widely used as protective layers in plasma etching equipment, but achieving stoichiometric films with high deposition rates remains a challenge. In this study, Y₂O₃ films were fabricated by a medium-frequency reactive magnetron sputtering (MF-RMS) technique. The oxygen flow and target control voltage were regulated through a closed-loop feedback control system, which effectively solved the problem. The microstructure, mechanical, optical, and plasma etching properties were systematically investigated. The results showed that near-stoichiometric films can achieve a relatively high deposition rate. Increasing the deposition temperature induced a structural transition in the Y₂O₃ film from a predominantly cubic phase to a mixture of cubic and monoclinic phases. For Y₂O₃ films deposited at room temperature, increasing the bias voltage increased the deposition rate but reduced hardness and elastic modulus. The Y₂O₃ film deposited at 300 °C in the near-metallic mode exhibited the highest hardness and elastic modulus, reaching 13.3 GPa and 222.0 GPa, respectively. All Y₂O₃ films exhibited excellent transmittance and resistance to plasma etching. This study provides an effective protective strategy for semiconductor etching chambers.

In this study, three different substrate holder shapes—trapezoidal, circular frustum, and adjustable cyclic—were designed and optimized to enhance the quality of polycrystalline diamond films grown using microwave plasma chemical vapor deposition (MPCVD). Simulation results indicate that altering the shape of the substrate holder leads to a uniform distribution of the electric field on the surface, significantly suppressing the formation of secondary plasma. This design ensures a more even distribution of the temperature field and plasma environment on the substrate holder, resulting in a heart-shaped distribution. Polycrystalline diamond films were synthesized under these three different substrate holder conditions, and their morphology and crystal quality were characterized using optical microscopy, Raman spectroscopy, and high-resolution X-ray diffraction. Under conditions of 5 kW power and 90 Torr pressure, the adjustable cyclic substrate holder produced high-quality 3-inch diamond films with low stress and narrow Raman full width at half maximum (FWHM). The results confirm the reliability of the simulations and the effectiveness of the adjustable cyclic substrate holder. This approach provides a viable method for scaling up the size and improving the quality of polycrystalline diamond films for future applications.