Transversal Type Piezoelectric Resonator Using ZnO Thin Film on Micro-Fabricated Elinver (Fe-Ni-Cr-Ti) Alloy

1998 ◽  
Vol 518 ◽  
Author(s):  
Y. Yoshino
Keyword(s):  
Thin Film ◽  
Temperature Coefficient ◽  
Cross Section ◽  
Wet Etching ◽  
Ti Alloy ◽  
Zno Thin Film ◽  
Electrical Characteristics ◽  
Piezoelectric Resonator ◽  
Axis Orientation ◽  
Temperature Coefficient Of Frequency

AbstractA transversal type 3.58MHz piezoelectric resonator has been fabricated using piezoelectric ZnO thin film on ELINVER (Fe-Ni-Cr-Ti ) alloy. The ZnO/ELINVER structure piezoelectric resonator has been designed to have 2 ppm temperature coefficient of frequency (TCF) per degree from -20 degrees to 80 degrees centigrade. The temperature coefficient of ELINVER alloy can be controlled to cancel the TCF of ZnO thin film by heat annealing. The ZnO thin film on ELINVER alloy shows c-axis orientation. The c-axis orientation of the ZnO thin film is strongly influenced by the surface roughness of the ELINVER alloy. The wet etching process has been adopted to shape the resonator made from ELINVER alloy substrate. The cross section of the resonator is a structure tapered about 10 degrees, created using different sized photo masks on each side of the ELINVER surface. The tapered cross section of the transversal type resonator greatly improves the frequency characteristics of the resonator. The electrical characteristics of the resonator after the improvement include a resonance frequency of 3.58MHz trimmed by a YAG laser, and resonance resistance of about 200 Ω. The temperature coefficient of frequency is about 1.5 ppm per degree at a temperature range of-20 degrees to 80 degrees centigrade.

ELECTRICAL AND OPTICAL PROPERTIES OF ZnO THIN FILMS PREPARED BY R.F. MAGNETRON SPUTTERING

2011 ◽  
Vol 25 (20) ◽  
pp. 2741-2749 ◽  
Author(s):  
J. C. ZHOU ◽  
L. LI ◽  
L. Y. RONG ◽  
B. X. ZHAO ◽  
Y. M. CHEN ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
Oxide Thin Film ◽  
Zno Thin Films ◽  
Zno Thin Film ◽  
Electrical And Optical Properties ◽  
Axis Orientation ◽  
Sputtering Power

High transparency and conductivity of transparent conducting oxide thin film are very important for improving the efficiency of solar cells. ZnO thin film is a better candidate for transparent conductive layer of solar cell. N-type ZnO thin films were prepared by radio-frequency magnetron sputtering on glass substrates. ZnO thin films underwent annealing treatment after deposition. The influence of the sputtering power on the surface morphology, the electrical and optical properties were studied by AFM, XRD, UV2450 and HMS-3000. The experimental results indicate that the crystal quality of ZnO thin film is improved and all films show higher c-axis orientation with increasing sputtering power from 50 to 125 W. The average transparency of ZnO thin films is higher than 90% in the range of 400–900 nm between the sputtering power of 50–100 W. After the rapid thermal annealing at 550°C for 300 s under N2 ambient, the minimum resistivity reach to 10-2Ω⋅ cm .

scholarly journals Temperature dependence of the electrical characteristics up to 370 K of amorphous In-Ga-ZnO thin film transistors

2016 ◽  
Vol 56 ◽  
pp. 29-33 ◽  
Author(s):  
M. Estrada ◽  
M. Rivas ◽  
I. Garduño ◽  
F. Avila-Herrera ◽  
A. Cerdeira ◽  
...  
Keyword(s):  
Thin Film ◽  
Temperature Dependence ◽  
Thin Film Transistors ◽  
Zno Thin Film ◽  
Electrical Characteristics

The Improvement of Temperature Coefficient of Frequency in Thin Film Bulk Acoustic Wave Resonator using Secondary Harmonics

2002 ◽  
Vol 741 ◽  
Author(s):  
Yukio Yoshino ◽  
Masaki Takeuchi ◽  
Hajime Yamada ◽  
Yoshihiko Goto ◽  
Tadashi Nomura ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Temperature Coefficient ◽  
Finite Element Method Simulation ◽  
Thickness Ratio ◽  
Bulk Acoustic Wave ◽  
Bulk Acoustic Wave Resonator ◽  
Wave Resonator ◽  
Film Bulk ◽  
Temperature Coefficient Of Frequency

ABSTRACTWe have succeeded in making an 870MHz-range thin film bulk acoustic wave (BAW) resonator that has a small temperature coefficient of frequency (TCF) using secondary harmonics. The 870MHz-range BAW resonator has been requested to have nearly zero TCF, because it will be used in an oscillator for remote keyless entry systems. The BAW resonator has composite structure that consists of Al electrodes and ZnO/SiO2. We directed our attention to the fact that ZnO and Al have negative TCF, and SiO2 has a positive one. It is theoretically possible to make zero TCF BAW resonators by optimizing the thickness ratio of ZnO and SiO2. However, using fundamental resonance, TCF is so sensitive to the thickness ratio that it cannot be easily controlled by MEMS techniques. We founds in finite element method simulation and confirmed by experiment that the TCF of secondary harmonics has a local minimum when changing the ZnO/SiO2 thickness ratio. As the result, a nearly zero TCF resonator without strict control of ZnO/SiO2 thickness ratio has been realized by adopting Al/ZnO/SiO2/ZnO/Al/SiO2 structure and combining thermal oxidized Si and sputtered SiO2. The resonator has the TCF of -1.86ppm/degree in the range of −40 to 85 degrees centigrade.

scholarly journals Channel Defect Profiling and Passivation for ZnO Thin-Film Transistors

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1186
Author(s):  
Soo Cheol Kang ◽  
So Young Kim ◽  
Sang Kyung Lee ◽  
Kiyung Kim ◽  
Billal Allouche ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Oxygen Vacancies ◽  
Drain Current ◽  
Vacuum Treatment ◽  
Trap Level ◽  
Zno Thin Film ◽  
Electrical Characteristics ◽  
Bias Stress ◽  
Trap Assisted Tunneling

The electrical characteristics of Zinc oxide (ZnO) thin-film transistors are analyzed to apprehend the effects of oxygen vacancies after vacuum treatment. The energy level of the oxygen vacancies was found to be located near the conduction band of ZnO, which contributed to the increase in drain current (ID) via trap-assisted tunneling when the gate voltage (VG) is lower than the specific voltage associated with the trap level. The oxygen vacancies were successfully passivated after the annealing of ZnO in oxygen ambient. We determined that the trap-induced Schottky barrier lowering reduced a drain barrier when the drain was subjected to negative bias stress. Consequentially, the field effect mobility increased from 8.5 m2 V−1·s−1 to 8.9 m2 V−1·s−1 and on-current increased by ~13%.

Effect of Buffer Electrodes in Crystallization of Zinc Oxide Thin Film for Thin Film Bulk Acoustic Wave Resonator

1999 ◽  
Vol 605 ◽  
Author(s):  
Y. Yosho ◽  
N. Tsukai ◽  
K. Inoue ◽  
M. Takeuchi ◽  
T. Nomura ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Oxide Thin Film ◽  
Bulk Acoustic Wave ◽  
Zno Thin Film ◽  
Axis Orientation ◽  
Au Electrode ◽  
Bulk Acoustic Wave Resonator ◽  
Wave Resonator ◽  
Film Bulk

AbstractA thin film bulk acoustic wave resonator (TBAR) has been fabricated using a ZnO thin film on a SiO2 diaphragm by MEMs techniques. The ZnO/SiO2 structure TBAR can be designed to cancel a temperature coefficient of frequency (TCF) by the ZnO/SiO2 thickness ratio, because the TCF of ZnO is negative, and that of SiO2 is positive. The ZnO thin film on the SiO2 shows a c-axis orientation almost equivalent to that of the ZnO thin film on a glass substrate by RF sputtering. However, the crystallinity of the ZnO thin film is influenced by the surface conditions of substrates. ZnO thin films have been deposited on Au/Cr, Au/NiCr and Au/Ti. The Au/Ti/ZnO/Au/Ti/SiO2 structure TBAR shows the best resonant characteristics in this experiment. The resonant characteristics of the TBAR depend on the crystallinity of the ZnO thin film. The resonant resistance of the TBAR at 205MHz using a Au/Ti under electrode is about 10% less than that using an Au/Cr electrode. The x-ray diffraction result shows that the crystallinity of ZnO is greatly influenced by the crystallinity of the lower electrode. The buffer layer between an Au electrode and substrate has an influence on both the crystallinity of the ZnO thin film and the resonant characteristics of the TBAR through the Au electrode.

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