A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etc...A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.展开更多
Rare earth Sm＋ ion doped potassium hydrogen phthalate （KHP） single crystal was grown by slow evaporation technique. Single crystal and powder X-ray diffraction analyses confirm the crystalline perfection of Sm＋ io...Rare earth Sm＋ ion doped potassium hydrogen phthalate （KHP） single crystal was grown by slow evaporation technique. Single crystal and powder X-ray diffraction analyses confirm the crystalline perfection of Sm＋ ion doped KHP crystal. The functional groups of pure and Sm＋ ion doped KHP crystals were identified by Fourier transform infrared spectroscopy （FTIR） spectral studies. Thermogravimetric and differential thermal analyses were carried out to study the thermal behavior of the grown crystals. UV-Vis studies explored the optical transmittance of the grown crystals in the entire visible region. The mechanical strength and etching studies were performed to assess the perfection of the pure and Sm＋ ion doped KHP crystals. The refractive index and birefringence properties of the grown crystal were analyzed. The second harmonic generation efficiency of Sm＋ ion doped KHP crystals was observed by Kurtz-Perry powder test.展开更多
文摘A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.
基金One of the authors(M.Krishna Kumar)acknowledges Council of Scientific and Industrial Research(CSIR),New Delhi,India for providing financial support(Project No.03(1200)/EMR-Ⅱ)
文摘Rare earth Sm＋ ion doped potassium hydrogen phthalate （KHP） single crystal was grown by slow evaporation technique. Single crystal and powder X-ray diffraction analyses confirm the crystalline perfection of Sm＋ ion doped KHP crystal. The functional groups of pure and Sm＋ ion doped KHP crystals were identified by Fourier transform infrared spectroscopy （FTIR） spectral studies. Thermogravimetric and differential thermal analyses were carried out to study the thermal behavior of the grown crystals. UV-Vis studies explored the optical transmittance of the grown crystals in the entire visible region. The mechanical strength and etching studies were performed to assess the perfection of the pure and Sm＋ ion doped KHP crystals. The refractive index and birefringence properties of the grown crystal were analyzed. The second harmonic generation efficiency of Sm＋ ion doped KHP crystals was observed by Kurtz-Perry powder test.
