Study on Effects of Hydrogen Flow Rates on the Properties of ZnO Thin Film Deposited by Facing Targets Sputtering System

Nanostructured zinc oxide (ZnO) thin films were deposited on glass substrates using radio frequency (RF) magnetron sputtering system at different oxygen flow rates ranges between 0 to 40 sccm. Field emission scanning electron microscopy (FESEM) images was revealed that nanocolumnar ZnO structure thin films are produced on the substrates using high purity ZnO as the target at RF power of 250 W in the argon and oxygen gas mixture ambient. The XRD spectra reveal that the deposited films are preferentially grown along the c-axis indicating high ZnO crystallinity. The ultraviolet-visible (UV-Vis) spectra show that all samples are very transparent in the visible region (400 – 800 nm) with average transparency above 80 %. The photocurrent properties indicate that ZnO thin film prepared at oxygen flow rate of 20 sccm has the optimum characteristic for ultraviolet sensor applications. This finding suggested that the oxygen flow rates play important role and has critical value for semiconducting nanocolumnar ZnO growth in the sputtering system, which can produce ZnO thin film with high sensitivity of ultraviolet detection.

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Effects of Thermal Annealing on the Characteristics of High Frequency FBAR Devices

Coatings ◽

10.3390/coatings11040397 ◽

2021 ◽

Vol 11 (4) ◽

pp. 397

Author(s):

Yu-Chen Chang ◽

Ying-Chung Chen ◽

Bing-Rui Li ◽

Wei-Che Shih ◽

Jyun-Min Lin ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Thermal Annealing ◽

Electromechanical Coupling ◽

Zno Thin Films ◽

Electromechanical Coupling Coefficient ◽

Back Side ◽

Zno Thin Film ◽

Frequency Responses ◽

Sputtering System

In this study, piezoelectric zinc oxide (ZnO) thin film was deposited on the Pt/Ti/SiNx/Si substrate to construct the FBAR device. The Pt/Ti multilayers were deposited on SiNx/Si as the bottom electrode and the Al thin film was deposited on the ZnO piezoelectric layer as the top electrode by a DC sputtering system. The ZnO thin film was deposited onto the Pt thin film by a radio frequency (RF) magnetron sputtering system. The cavity on back side for acoustic reflection of the FBAR device was achieved by KOH solution and reactive ion etching (RIE) processes. The crystalline structures and surface morphologies of the films were analyzed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optimized as-deposited ZnO thin films with preferred (002)-orientation were obtained under the sputtering power of 80 W and sputtering pressure of 20 mTorr. The crystalline characteristics of ZnO thin films and the frequency responses of the FBAR devices can be improved by using the rapid thermal annealing (RTA) process. The optimized annealing temperature and annealing time are 400 °C and 10 min, respectively. Finally, the FBAR devices with structure of Al/ZnO/Pt/Ti/SiNx/Si were fabricated. The frequency responses showed that the return loss of the FBAR device with RTA annealing was improved from −24.07 to −34.66 dB, and the electromechanical coupling coefficient (kt2) was improved from 1.73% to 3.02% with the resonance frequency of around 3.4 GHz.

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New sputtering system for manufacturing ZnO thin‐film SAW Devices

Journal of Vacuum Science and Technology ◽

10.1116/1.569817 ◽

1978 ◽

Vol 15 (4) ◽

pp. 1601-1604 ◽

Cited By ~ 18

Author(s):

Kenzo Ohji ◽

Osamu Yamazaki ◽

Kiyotaka Wasa ◽

Shigeru Hayakawa

Keyword(s):

Thin Film ◽

Zno Thin Film ◽

Saw Devices ◽

Sputtering System

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4174. New sputtering system for manufacturing ZnO thin-film SAW devices. (USA)

Vacuum ◽

10.1016/s0042-207x(79)80935-5 ◽

1979 ◽

Vol 29 (11-12) ◽

pp. 459

Keyword(s):

Thin Film ◽

Zno Thin Film ◽

Saw Devices ◽

Sputtering System

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Thermal performance of LED fixed on CVD processed ZnO thin film on Al substrates at various O2 gas flow rates

AIMS Materials Science ◽

10.3934/matersci.2018.2.246 ◽

2018 ◽

Vol 5 (2) ◽

pp. 246-256 ◽

Cited By ~ 2

Author(s):

Nur Jassriatul Aida binti Jamaludin ◽

◽

Shanmugan Subramani

Keyword(s):

Thin Film ◽

Thermal Performance ◽

Gas Flow ◽

Zno Thin Film ◽

Flow Rates

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In−Zn−O Thin Films with Hydrogen Flow

Coatings ◽

10.3390/coatings9080485 ◽

2019 ◽

Vol 9 (8) ◽

pp. 485 ◽

Cited By ~ 2

Author(s):

Kim ◽

Yoon ◽

Jin ◽

Bang ◽

Song

Keyword(s):

Thin Films ◽

Absorption Coefficient ◽

Mechanical Stability ◽

Optical Transmittance ◽

Hydrogen Impurity ◽

Promising Candidate ◽

Flow Rates ◽

Hydrogen Flow ◽

Average Change ◽

Sputtering System

Amorphous In−Zn−O thin films were deposited with various hydrogen flow rates using a magnetron sputtering system. With the addition of hydrogen, the mechanical stability of the films was dramatically improved without any degradation of electrical properties and optical transmittance. The average change in the resistance of the sample deposited at a hydrogen flow rate of 0.4% was approximately six times lower than that in the sample deposited without hydrogen. Both, the compressive residual stress and absorption coefficient of the sample, decreased with hydrogen flow, indicating similar trends with the average change in the resistance. The absorption coefficient near 3.1 eV indicated that subgap state defects also decreased with increasing hydrogen flow rates. It was confirmed that the improvement in mechanical stability was derived from the suppression of subgap defects due to the hydrogen impurity. Thus, we demonstrated that hydrogen is a promising candidate for stabilizing the mechanical properties of oxide thin films.

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