Impact of thermal-induced sapphire substrate erosion on material and photodetector characteristics of sputtered Ga2O3 films

Li, Hui; Yuan, Shuo‐Huang; Huang, Tsun-Min; Chen, Hsuan-Jen; Lu, Fu-Hsing; Zhang, Sam; Wuu, Dong Sing

doi:10.1016/j.jallcom.2020.153755

Cited by 30 publications

(18 citation statements)

References 38 publications

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“…The maximum responsivity was blue-shifted, which was due to the wide band gap of Ga 2 O 3 films, as summarized in Table . These results were published in our previous study …”

Section: Resultssupporting

confidence: 88%

“…and Schewski et al, who demonstrated that layers grown on the (100) orientation suffer from a high density of twins and SFs, owing to the relaxation of lattice strain. In contrast, high-resolution TEM imaging of sputtered β-Ga 2 O 3 (2̅01)/sapphire under RTA treatment at 1000 °C in prior studies did not show massive TBs and SFs . The (100) preferred orientation is the driving force of TBs and SFs.…”

Section: Resultsmentioning

confidence: 77%

“…After rapid thermal annealing (RTA) treatments, the element concentration distribution in samples remained unchanged even after being annealed at 1000 °C. There is no obvious interdiffusion of Ga and Si, unlike our previous study on the interdiffusion of Ga and Al for the Ga 2 O 3 /sapphire heterostructure …”

Section: Resultsmentioning

confidence: 99%

“…There is no obvious interdiffusion of Ga and Si, unlike our previous study on the interdiffusion of Ga and Al for the Ga 2 O 3 /sapphire heterostructure. 40 X-ray diffraction (XRD) analyses were performed to reveal the crystallinity of the annealed β-Ga 2 O 3 films. The resulting XRD θ−2θ scans of the as-deposited Ga 2 O 3 samples thermally treated by RTA processes at various temperatures ranging from 700 to 1000 °C are shown in Figure 2a,b (thicknesses of 100 and 200 nm, respectively).…”

Section: Resultsmentioning

confidence: 99%

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Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors

et al. 2021

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It is generally known that a layer of amorphous silicon oxide (SiO 2 ) naturally exists on the surface of silicon, resulting in the growth of gallium oxide (Ga 2 O 3 ) that is no longer affected by substrate crystallinity during sputtering. This work highlights the formation energy between the native amorphous nano-oxide film formed on the Si substrate and monoclinic β-Ga 2 O 3 dominating the preferred orientation prepared for deep ultraviolet photodetectors. The latter were deposited on p-type silicon (p-Si) with (111) orientation using radio frequency sputtering at 600 °C and post rapid thermal annealing (RTA). The X-ray diffraction (XRD) results indicate both as-deposited and postannealing films with the (400) preferred orientation for a layer thickness of 100 nm. However, slight random orientation with the amorphous structure is mixed in the preferred one for the asdeposited film with a thickness of 200 nm and reduced after being annealed at 800 °C, which is observed by XRD and transmission electron microscopy. Meanwhile, thermal-induced massive twin boundaries (TBs) and stacking faults (SFs) were generated when annealed at 1000 °C, owing to the relaxation of lattice strain by the coherent interface. The interfacial bonding energy per unit area (E i ) between β-Ga 2 O 3 films with various facets ((001), ( 010), (100), and (2̅ 01)) and amorphous SiO 2 was calculated using density functional theory. The E i of β-Ga 2 O 3 (100)/SiO 2 reveals the highest value (0.289 eV/Å 2 ), which is consistent with the (100) preferred orientation of deposited films. The (100) preferred orientation is the driving force for TBs and SFs. The discrimination of responsivities and the photo/dark current contrast ratio (I ph /I dark ) are inversely proportional to the amorphous structure, grain boundaries, TBs, and SFs. Therefore, optimum metal−semiconductor−metal photodetector performance is achieved for RTAtreated samples at 800 °C with an I ph /I dark of 3.91 × 10 2 and a responsivity of 0.702 A/W (λ peak = 230 nm) at 5 V bias for a 200 nm thin film.

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“…The maximum responsivity was blue-shifted, which was due to the wide band gap of Ga 2 O 3 films, as summarized in Table . These results were published in our previous study …”

Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors

et al. 2021

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“…ZnGa 2 O 4 possesses a wide bandgap in the region of 4.4–5.2 eV [ 8 , 9 ]. Its inherent chemical and thermal characteristics in a harsh environment along with high breakdown voltage make ZnGa 2 O 4 a potential candidate for high-voltage devices, such as transistors and MOSFETs [ 10 ]. Wide bandgap semiconductors improve the efficiency of power-conversion stages, and they may be utilized instead of silicon in the production of voltage converters, power MOSFETs, and high-efficiency Schottky diodes.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

et al. 2021

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Spinel ZnGa2O4 films were grown on c-plane sapphire substrates at the substrate temperature of 400 °C by radio-frequency magnetron sputtering. Post thermal annealing was employed at the annealing temperature of 700 °C in order to enhance their crystal quality. The effect of thermal annealing on the microstructural and optoelectronic properties of ZnGa2O4 films was systematically investigated in various ambiences, such as air, nitrogen, and oxygen. The X-ray diffraction patterns of annealed ZnGa2O4 films showed the crystalline structure to have (111) crystallographic planes. Transmission electron micrographs verified that ZnGa2O4 film annealed under air ambience possesses a quasi-single-crystalline structure. This ZnGa2O4 film annealed under air ambience exhibited a smooth surface, an excellent average transmittance above 82% in the visible region, and a wide bandgap of 5.05 eV. The oxygen vacancies under different annealing ambiences were revealed a substantial impact on the material and photodetector characteristics by X-ray photoelectron spectrum investigations. ZnGa2O4 film exhibits optimal performance as a metal-semiconductor-metal photodetector when annealed under air ambience. Under these conditions, ZnGa2O4 film exhibits a higher photo/dark current ratio of ~104 order, as well as a high responsivity of 2.53 A/W at the bias of 5 V under an incident optical light of 240 nm. These results demonstrate that quasi-single-crystalline ZnGa2O4 films have significant potential in deep-ultraviolet applications.

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A Strategic Review on Gallium Oxide Based Deep‐Ultraviolet Photodetectors: Recent Progress and Future Prospects

Kaur

Kumar

2021

Advanced Optical Materials

265

153

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With the use of UV‐C radiation sterilizers on the rise in the wake of the recent pandemic, it has become imperative to have health safety systems in place to curb the ill‐effects on humans. This requires detection systems with suitable spectral response to the “invisible to the naked eye” radiation leaks with utmost sensitivity and swiftness. State of the art deep‐UV photodetectors based on the wide bandgap material gallium oxide have achieved responsivities up to few hundred A W−1 while the minimum response time achieved is few hundred nanoseconds. However, due to the trade‐off between these two key parameters, the ultimate performance of the photodetectors remains inadequate. The focus here is to give a thorough review of the gallium oxide based photodetectors, their recent progress and future prospects. This review highlights the fundamental physics and the key parameters such as dark current, responsivity, and response time with their dependence on the material properties. Exploration of the reasons behind current scenario in the field of gallium oxide is comprehensively and critically analyzed. The key challenges which limit device performance and inhibit the realization of real‐world practical detectors are also described. The lacunae currently plaguing the field is also discussed with possible remedial solutions.

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Impact of thermal-induced sapphire substrate erosion on material and photodetector characteristics of sputtered Ga2O3 films

Cited by 30 publications

References 38 publications

Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors

Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors

The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

A Strategic Review on Gallium Oxide Based Deep‐Ultraviolet Photodetectors: Recent Progress and Future Prospects

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Impact of thermal-induced sapphire substrate erosion on material and photodetector characteristics of sputtered Ga2O3 films

Cited by 30 publications

References 38 publications

Role of Interfacial Oxide in the Preferred Orientation of Ga2O3 on Si for Deep Ultraviolet Photodetectors

Role of Interfacial Oxide in the Preferred Orientation of Ga2O3 on Si for Deep Ultraviolet Photodetectors

The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

A Strategic Review on Gallium Oxide Based Deep‐Ultraviolet Photodetectors: Recent Progress and Future Prospects

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Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors

Role of Interfacial Oxide in the Preferred Orientation of Ga₂O₃ on Si for Deep Ultraviolet Photodetectors