The energy band alignment at the atomic layer deposited Al2O3/β-Ga2O3 interface with CHF3 treatment was characterized by x-ray photoelectron spectroscopy and secondary ion mass spectrometry(SIMS).With additional CHF3...The energy band alignment at the atomic layer deposited Al2O3/β-Ga2O3 interface with CHF3 treatment was characterized by x-ray photoelectron spectroscopy and secondary ion mass spectrometry(SIMS).With additional CHF3 plasma treatment,the conduction band offset increases from 1.95±0.1 eV to 2.32±0.1 eV;and the valence band offset decreases from 0.21±0.1 eV to-0.16±0.1 eV.As a result,the energy band alignment changes from type I to type II.This energy band alignment transition could be attributed to the downshift of the core-level of Ga 3d,resulting from the Ga–F bond formation in the F-rich interfacial layer,which is confirmed by the SIMS results.展开更多
The density-normalized effective ionization coefficient （α - η）/N （α and η are the ionization and attachment coefficients respectively）, the electron drift velocity Ve and density- normalized longitudinal diff...The density-normalized effective ionization coefficient （α - η）/N （α and η are the ionization and attachment coefficients respectively）, the electron drift velocity Ve and density- normalized longitudinal diffusion coefficient NDL in trifluoromethane （CHF3） and carbon tetraflu- oride （CF4） were measured using a pulsed Townsend technique over a wide E/N range. From the plots of （α- η）/N, we have derived the limiting field strength, （E/N）nm, which is valid for the analysis of insulation characteristics and applications to power equipment. Comparisons of the electron swarms parameters between CHF3 and CFa have been performed, and the global warming potential （GWP） is also taken into account.展开更多
An experimental study of the dependence of SiO2 waveguide side wall roughness on the etch condi- tions and etch masks in CHF3/O2 based reactive ion etching plasma was reported. When working under standard low-pressure...An experimental study of the dependence of SiO2 waveguide side wall roughness on the etch condi- tions and etch masks in CHF3/O2 based reactive ion etching plasma was reported. When working under standard low-pressure （20mtorr） etching conditions, a novel etch roughening phenomenon has been observed in the plasma, that is, the roughness of the etched front surface increases with the amount of material etched, independent of etch rate, RF power, and gas composition. Besides, the etched underlying side wall will be tapered as the upper SU-8 resist pattern degradation transfers downward. A process using double-layered mask, consisting of SU-8 resist and thin Chromium film, was developed for improving the side wall smoothness. Based on the studies, SiO2/Si channel waveguides with the propagation loss less than 0. 07dB/cm were fabricated at last.展开更多
A-C:F, H film have been studied because of their low dielectric constant for application in interlayer dielectric in ULSC. These films were deposited by ECR plasma Reactor with CHF3 and C6H6 mixture as source gas. Th...A-C:F, H film have been studied because of their low dielectric constant for application in interlayer dielectric in ULSC. These films were deposited by ECR plasma Reactor with CHF3 and C6H6 mixture as source gas. The effects of microwave power, pressure and CHF3/C6H6 ratios on the film deposition rates have been investigated. The fluorocarbon and hydrocarbon radical species in the plasma discharges were analyzed by using the optical emission spectra. It demonstrates that CF2, CF and CH radicals play the important roles in the films being formed.展开更多
基金Supported by the Guangdong Province Key Technologies Research and Development Program(Grant No.2019B010128001)the National Natural Science Foundation of China(Grant No.61774041)the Shanghai Science and Technology Innovation Program(Grant No.19520711500)。
文摘The energy band alignment at the atomic layer deposited Al2O3/β-Ga2O3 interface with CHF3 treatment was characterized by x-ray photoelectron spectroscopy and secondary ion mass spectrometry(SIMS).With additional CHF3 plasma treatment,the conduction band offset increases from 1.95±0.1 eV to 2.32±0.1 eV;and the valence band offset decreases from 0.21±0.1 eV to-0.16±0.1 eV.As a result,the energy band alignment changes from type I to type II.This energy band alignment transition could be attributed to the downshift of the core-level of Ga 3d,resulting from the Ga–F bond formation in the F-rich interfacial layer,which is confirmed by the SIMS results.
基金supported by National Natural Science Foundation of China (No. 51177101)
文摘The density-normalized effective ionization coefficient （α - η）/N （α and η are the ionization and attachment coefficients respectively）, the electron drift velocity Ve and density- normalized longitudinal diffusion coefficient NDL in trifluoromethane （CHF3） and carbon tetraflu- oride （CF4） were measured using a pulsed Townsend technique over a wide E/N range. From the plots of （α- η）/N, we have derived the limiting field strength, （E/N）nm, which is valid for the analysis of insulation characteristics and applications to power equipment. Comparisons of the electron swarms parameters between CHF3 and CFa have been performed, and the global warming potential （GWP） is also taken into account.
文摘An experimental study of the dependence of SiO2 waveguide side wall roughness on the etch condi- tions and etch masks in CHF3/O2 based reactive ion etching plasma was reported. When working under standard low-pressure （20mtorr） etching conditions, a novel etch roughening phenomenon has been observed in the plasma, that is, the roughness of the etched front surface increases with the amount of material etched, independent of etch rate, RF power, and gas composition. Besides, the etched underlying side wall will be tapered as the upper SU-8 resist pattern degradation transfers downward. A process using double-layered mask, consisting of SU-8 resist and thin Chromium film, was developed for improving the side wall smoothness. Based on the studies, SiO2/Si channel waveguides with the propagation loss less than 0. 07dB/cm were fabricated at last.
文摘A-C:F, H film have been studied because of their low dielectric constant for application in interlayer dielectric in ULSC. These films were deposited by ECR plasma Reactor with CHF3 and C6H6 mixture as source gas. The effects of microwave power, pressure and CHF3/C6H6 ratios on the film deposition rates have been investigated. The fluorocarbon and hydrocarbon radical species in the plasma discharges were analyzed by using the optical emission spectra. It demonstrates that CF2, CF and CH radicals play the important roles in the films being formed.
