Jipo Huang

Preparation and Characterization of MgO Thin Films by a Novel Sol-Gel Method

MgO thin films have been prepared on Si substrates by a novel and simple sol-gel method using magnesium nitrate and collodion as starting material. Solutions consisting of magnesium nitrate in a mixture of collodion and ethanol were spin-coated onto silicon substrates. It was found that collodion was a necessary component to form stable sols and the crystallization and structures were clearly dependent on the amount of the collodion and the annealing temperature. The MgO thin films with good crystallization were obtained after annealing at 800°C. Meanwhile, the microstructure of the MgO films was examined by transmission electron microscopy and atomic force microscopy.

Preparation of AlN thin films by nitridation of Al-coated Si substrate

AlN thin films have been grown on Al-coated Si(100) and Si(111) substrates by using nitridation in high-purity nitrogen ambient, where the Al layer was previously deposited on Si by ultra-high vacuum (UHV) electron beam evaporation. The temperature of nitridation was found to play an important role in the formation of AlN films. XRD results showed AlN films formed by nitridation at 1000°C for 30 min exhibited good crystallinity with the preferred orientation of (002) for both Si(111) and Si(100) cases. Other analysis techniques, like Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy have been used to evidence the formation and purity of the AlN films. Scanning electron microscope observations of the films revealed a closely-packed granular texture.

Effect of annealing on SiC thin films prepared by pulsed laser deposition

Abstract Crystalline cubic SiC thin films were successfully fabricated on Si(100) substrates by using laser deposition combined with a vacuum annealing process. The effect of annealing conditions on the structure of the thin films was investigated by X-ray diffraction and Fourier transform infrared spectroscopy. It was demonstrated that amorphous SiC films deposited at 800°C could be transformed into crystalline phase after being annealed in a vacuum and that the annealing temperature played an important role in this transformation, with an optimum annealing temperature of 980°C. Results of X-ray photoelectron spectroscopy revealed the approximate stoichiometry of the SiC films. The characteristic microstructure displayed in a scanning electron microscope image of the films was indicative of epitaxial growth along the (100) plane.

Total dose radiation effects of Au/PbZr0.52Ti0.48O3/YBa2Cu3O7-δ capacitors

PbZr0.52Ti0.48O3/YBa2Cu3O7−δ (PZT/YBCO) thin films have been fabricated on Y2O3 stabilized zirconate (YSZ) substrates by a pulsed excimer laser deposition (PLD) method. In order to investigate total dose radiation effects on the Au/PZT/YBCO ferroelectric capacitor, the capacitance–voltage (C–V) curves and the retained polarization property of the capacitor have been measured before and after γ-ray irradiation. The results showed that, with an increased total dose, the retained polarization and the dielectric constant decreased, but the coercive field drifted towards positive voltage direction. This is caused by charges trapped by defects in the PZT capacitor during irradiation.

Structural and electrical characteristics of oxygen-implanted 6H-SiC

Silicon carbide is an important wide band gap semiconductor for high-temperature, high-voltage, high-power and high-frequency devices. Ion implantation is an important aspect for both fundamental r ...

Variation of strain/defects in H+-implanted single crystal silicon

Abstract Single crystal silicon samples were implanted with H + ions at an energy of 30 KeV, and a dose of 4×10 16 /cm 2 . These samples were annealed in the temperature range from 100°C to 500°C. Four-crystal X-ray diffractometer (FCXRD), cross-sectional transmission electron microscopy (XTEM), Rutherford backscattering spectroscopy and channeling (RBS/C) were used to characterize the distribution and magnitude of the strain and extended defects in the samples. Elastic recoil detection analysis (ERDA) was used to measure the redistribution of hydrogen in Si samples during annealing. Strain distributions in the samples were simulated from the rocking curves by computer. The results help to understand the evolution of the strain and defects during annealing in the high dose H + -implanted silicon samples.

Investigation of damage behaviour and isolation effect of n-type 6H-SiC by implantation of oxygen

Silicon carbide is an important wide-band-gap semiconductor for high temperature, high-voltage, high-power and high-frequency devices. Electrical isolation is an important aspect for device applications. In this report, oxygen ions, 70 keV with doses ranging from 5×1013 to 5×1015 cm-2, have been implanted into n-type 6H-SiC to investigate the possibility of forming a high-resistive layer. The damage behaviour and internal stress were checked by Rutherford backscattering spectroscopy and channelling, and an x-ray rocking curve, respectively. Atomic force microscope observations revealed that the surface morphology is quite sensitive to the implantation even at a dose of 1×1014 cm-2. After annealing in nitrogen at 1200 °C, no remarkable damage recovery could be seen if the deposit damage energy is over the critical value. Schottky structures of Au/SiC have been fabricated on the annealed samples and I-V curves of metal/SiC/InGeNi were measured at room temperature at both forward and reverse bias; the electrical isolation effect was observed at proper implantation dosages. The results indicated that there exists a dose window for electrical isolation.

Total dose radiation effects of Au/PbZr0.52Ti0.48O3/YBa2Cu3O7-delta/LaAlO3 ferroelectric capacitors

PbZr 0.52 Ti 0.48 O 3 /YBa 2 Cu 3 O 7-δ (PZT/YBCO) thin films have been fabricated on LaAlO 3 substrate by the pulsed laser excimer deposition method. In order to investigate total dose radiation effects by 60 Co γ-irradiation on the Au/PZT/YBCO ferroelectric capacitor, the capacitance voltage (C V) and the retained polarization properties of the capacitor were measured before and after γ-ray irradiation The results showed that. with the increment of the total dose, the retained polarization (ΔP) and the dielectric constant (e) decreased, but the absolute value of the negative and positive coercitive fields increased. It is due to the effect of charges trapped by defects in the PZT capacitor during irradiation.

A study of optical characteristics of damage in oxygen-implanted 6H-SiC

Oxygen ions, with an energy of 70 keV, and doses ranging from 5A—1013 to 5A—1015 cm-2, were implanted into 6H SiC. The damage energies were calculated as 0.93-93 eV/atom with the doses respectively. The dielectric function obtained from spectroscopic ellipsometry were quite sensitive to ion irradiation of the surface, while the first order Raman spectroscopy decreased in intensity with increasing O+ ion dose. The damage behavior characterized by optical measurements was in good agreement with characterization by Rutherford backscattering spectrometry and channeling and atomic force microscopy.

Epitaxial Pb(Zr0.52Ti0.48) O3/Y1Ba2Cu3O7-x Heterostructure Prepared by Pulsed Laser Deposition

C-axis oriented Y1Ba2Cu3O7-x (YBCO) thin films and PbZr0.52Ti0.48O3 (PZT)/(YBCO) heterostructures were deposited on single-crystal LaAlO3 by Nd:YAG pulsed laser deposition. The results showed that the YBCO films exhibited superconducting transition temperature above 86 K and ion beam channeling minimum yields χmin of 49%, indicating the relatively good quality of YBCO films deposited on the LaAlO3 substrate. The PZT films in situ grown on the YBCO films were epitaxially c-axis oriented with a saturation polarization and remanence as high as 57μC/cm2 and 39μC/cm2 (at 204 kV/cm), respectively. The coercive field of PZT films is about 55 kV/cm.