AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were inve...AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator （FBAR） may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.展开更多
AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of...AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.展开更多
The dispersion curves of bulk waves propagating in both AlN and ZnO film bulk acoustic resonators(FBARs)are presented to illustrate the mode flip of the thickness-extensional(TE)and 2nd thickness-shear(TSh2)modes.The ...The dispersion curves of bulk waves propagating in both AlN and ZnO film bulk acoustic resonators(FBARs)are presented to illustrate the mode flip of the thickness-extensional(TE)and 2nd thickness-shear(TSh2)modes.The frequency spectrum quantitative prediction(FSQP)method is used to solve the frequency spectra for predicting the coupling strength among the eigen-modes in AlN and ZnO FBARs.The results elaborate that the flip of the TE and TSh2 branches results in novel self-coupling vibration between the small-wavenumber TE and large-wavenumber TE modes,which has never been observed in the ZnO FBAR.Besides,the mode flip leads to the change in the relative positions of the frequency spectral curves about the TE cut-off frequency.The obtained frequency spectra can be used to predict the mode-coupling behaviors of the vibration modes in the AlN FBAR.The conclusions drawn from the results can help to distinguish the desirable operation modes of the AlN FBAR with very weak coupling strength from all vibration modes.展开更多
A highly c-axis-oriented aluminum nitride(Al N)thin film with smooth and crack-free surface was fabricated by an off-normal direct current(DC)sputtering method in a pure nitrogen atmosphere,in which the rotatable subs...A highly c-axis-oriented aluminum nitride(Al N)thin film with smooth and crack-free surface was fabricated by an off-normal direct current(DC)sputtering method in a pure nitrogen atmosphere,in which the rotatable substrate holder positioned in the middle of four side targets was a key approach to guarantee the grain growth with no tilt.The detailed effects of substrate angle on the c-axis orientation of Al N films were investigated by varying the substrate angle from 0°to 90°.Moreover,theoretical analysis and Monte Carlo(MC)simulation reveal that the oblique or even vertical angle could improve the lateral kinetic energy of sputtered atoms deposited on the growing film.A variety of examining techniques including X-ray diffraction(XRD),(002)peak rocking curve,scanning electron microscopy(SEM)were conducted to evaluate the angle dependence on the crystallographic orientation.These test results indicate that larger substrate angle is beneficial to the(002)growth of Al N thin film,and a fully c-axis textured Al N thin film is obtained at 90°with small surface roughness(R_(a))of 3.32 nm.展开更多
Self heating effects in silicon on insulator (SOI) devices limit the applicability of SOI materials in electronics in cases where high power dissipation is expected. AlN film as a potential candidate for buried insula...Self heating effects in silicon on insulator (SOI) devices limit the applicability of SOI materials in electronics in cases where high power dissipation is expected. AlN film as a potential candidate for buried insulator material in SOI structures is investigated. Ion beam enhanced deposition (IBED) is used to manufacture large area AlN films. SIMS measurements indicate the formation of AlN films. The characterization of the films reveals that the quality of the films strongly depends on the evaporation rate of Al. For the film with high quality deposited at 0.05 nm/s, it has higher component of N, excellent dielectric property and a smoother surface with roughness RMS value of 0.13 nm, and can be bonded directly at room temperature by the smart cut process. SOI structure with the AlN film as buried insulator has formed successfully for the first time, which is confirmed by XTEM micrograph.展开更多
基金supported by the National Natural Science Foundation of China (No.50872031)the Natural Science Foundation of Hubei Province,China (No.2008CDA018)
文摘AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator （FBAR） may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.
文摘AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.
基金Project supported by the National Natural Science Foundation of China(Nos.11872329,12192211,and 12072315)the Natural Science Foundation of Zhejiang Province of China(No.LD21A020001)+1 种基金the National Postdoctoral Program for Innovation Talents of China(No.BX2021261)the China Postdoctoral Science Foundation Funded Project(No.2022M722745)。
文摘The dispersion curves of bulk waves propagating in both AlN and ZnO film bulk acoustic resonators(FBARs)are presented to illustrate the mode flip of the thickness-extensional(TE)and 2nd thickness-shear(TSh2)modes.The frequency spectrum quantitative prediction(FSQP)method is used to solve the frequency spectra for predicting the coupling strength among the eigen-modes in AlN and ZnO FBARs.The results elaborate that the flip of the TE and TSh2 branches results in novel self-coupling vibration between the small-wavenumber TE and large-wavenumber TE modes,which has never been observed in the ZnO FBAR.Besides,the mode flip leads to the change in the relative positions of the frequency spectral curves about the TE cut-off frequency.The obtained frequency spectra can be used to predict the mode-coupling behaviors of the vibration modes in the AlN FBAR.The conclusions drawn from the results can help to distinguish the desirable operation modes of the AlN FBAR with very weak coupling strength from all vibration modes.
基金financially supported by the National Natural Science Foundation of China(Nos.U1832131 and51721005)Beijing Municipal Natural Science Foundation(No.3202034)the Natural Science Foundation of Hebei Province(No.E2018402097)。
文摘A highly c-axis-oriented aluminum nitride(Al N)thin film with smooth and crack-free surface was fabricated by an off-normal direct current(DC)sputtering method in a pure nitrogen atmosphere,in which the rotatable substrate holder positioned in the middle of four side targets was a key approach to guarantee the grain growth with no tilt.The detailed effects of substrate angle on the c-axis orientation of Al N films were investigated by varying the substrate angle from 0°to 90°.Moreover,theoretical analysis and Monte Carlo(MC)simulation reveal that the oblique or even vertical angle could improve the lateral kinetic energy of sputtered atoms deposited on the growing film.A variety of examining techniques including X-ray diffraction(XRD),(002)peak rocking curve,scanning electron microscopy(SEM)were conducted to evaluate the angle dependence on the crystallographic orientation.These test results indicate that larger substrate angle is beneficial to the(002)growth of Al N thin film,and a fully c-axis textured Al N thin film is obtained at 90°with small surface roughness(R_(a))of 3.32 nm.
文摘Self heating effects in silicon on insulator (SOI) devices limit the applicability of SOI materials in electronics in cases where high power dissipation is expected. AlN film as a potential candidate for buried insulator material in SOI structures is investigated. Ion beam enhanced deposition (IBED) is used to manufacture large area AlN films. SIMS measurements indicate the formation of AlN films. The characterization of the films reveals that the quality of the films strongly depends on the evaporation rate of Al. For the film with high quality deposited at 0.05 nm/s, it has higher component of N, excellent dielectric property and a smoother surface with roughness RMS value of 0.13 nm, and can be bonded directly at room temperature by the smart cut process. SOI structure with the AlN film as buried insulator has formed successfully for the first time, which is confirmed by XTEM micrograph.
