Deposition of  SiO<sub>2</sub> Layers on GaN by Photochemical Vapor Deposition

Chang, Shoou Jinn; Su, Yan Kuin; Chiou, Yu−Zung; Chiou, Jung Ran; Huang, Bor-Luen; Chang, Chin Sung; Chen, Jone F.

doi:10.1149/1.1534598

Cited by 29 publications

(22 citation statements)

References 33 publications

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“…Unlike SiO 2 layers grown by PECVD and LPD, no Si-H and Si-F related absorption at 2,260 cm Ϫ1 and 950 cm Ϫ1 could be observed from our photo-CVD SiO 2 layer. [16][17][18][19] The absence of these two modes also suggests the good quality of our photo-CVD SiO 2 layer because the remaining Si-H and Si-F bonds might degrade the electrical strength of the deposited-oxide films. [17][18][19] Figure 4 shows the XPS spectrum of our photo-CVD SiO 2 layer.…”

Section: Methodsmentioning

confidence: 99%

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AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

Wang

Chiou

Chang

et al. 2003

Journal of Elec Materi

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High-quality SiO 2 was successfully deposited onto GaN by photo-chemicalvapor deposition (photo-CVD) using a D 2 lamp as the excitation source. The AlGaN/GaN metal-oxide semiconductor, heterostructure field-effect transistors (MOSHFETs) were also fabricated with photo-CVD oxide as the insulating layer. Compared with AlGaN/GaN metal-semiconductor HFETs (MESHFETs) with similar structure, we found that we could reduce the gate-leakage current by more than four orders of magnitude by inserting the photo-CVD oxide layer in between the AlGaN/GaN and the gate metal. With a 2-m gate, it was found that the saturated I ds , maximum g m , and gate-voltage swing (GVS) of the fabricated nitride-based MOSHFET were 512 mA/mm, 90.7 mS/mm, and 6 V, respectively.

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Section: Methodsmentioning

confidence: 99%

“…A detailed study on the electrical properties of our photo-CVD SiO 2 on GaN will be published elsewhere. 16 …”

Section: Methodsmentioning

confidence: 99%

AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

Wang

Chiou

Chang

et al. 2003

Journal of Elec Materi

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“…During photo-CVD deposition, chamber pressure and substrate temperature were controlled at 0.9 Torr and 300°C, respectively. [16][17][18][19][20][21] Fourier transform infrared spectroscopy ͑FTIR͒ and atomic force microscopy ͑AFM͒ were then used to characterize the deposited photo-CVD films. Aluminum gate metal was subsequently thermally evaporated onto the sample surfaces to complete the fabrication of GaN MIS capacitors.…”

Section: Methodsmentioning

confidence: 99%

“…Using such a system, we successfully fabricated Al/photo-CVD SiO 2 /GaN MIS capacitors using SiH 4 and O 2 as the reactant gases, because the UV and VUV light emitted from a D 2 lamp can effectively decompose SiH 4 and O 2 . [16][17][18][19][20][21] It has been reported by many researchers that nitrogencontaining SiN x O y layers are good insulators. Because Si-N bonds are stronger than Si-O, Si-H, and Si-OH bonds, SiN x O y layers can provide better hot electron immunity, lower charge trapping, higher breakdown voltage, and better radiation hardness.…”

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confidence: 99%

GaN MIS Capacitors with Photo-CVD SiN[sub x]O[sub y] Insulating Layers

Chang¹,

Wang²,

Su³

et al. 2005

J. Electrochem. Soc.

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We report the deposition of high-quality SiO 2 and SiN x O y layers onto GaN/sapphire templates by photochemical vapor deposition ͑photo-CVD͒. It was found that the 0.845 nm root-mean-square roughness observed from the photo-CVD SiN x O y layer was much smaller than that observed from photo-CVD SiO 2 layer with the same thickness. GaN metal-insulator-semiconductor ͑MIS͒ capacitors with these insulating layers were also fabricated. With an applied electric field of 4 MV/cm, it was found that the leakage current densities were 1 ϫ 10 −8 and 6 ϫ 10 −7 A/cm 2 for the capacitors with photo-CVD SiN x O y and photo-CVD SiO 2 insulating layers, respectively. It was also found that the breakdown field of the capacitors with photo-CVD SiN x O y could reach 13 MV/cm. The interface state density at the SiN x O y /GaN interface was also found to be reasonably low.Gallium nitride ͑GaN͒ possesses excellent physical and electrical properties, such as wide bandgap, high breakdown field, high saturation electron drift velocity, and good thermal stability. These properties make it particularly suitable for applications in high-speed, high-power, and high-frequency electronic devices operating at elevated temperatures. In the past years, GaN-based transistors such as metal-semiconductor field-effect-transistors ͑MES-FETs͒, heterostructure FETs ͑HFETs͒, and high-electron-mobility transistors ͑HEMTs͒ have all been successfully developed. 1-4 However, the performances of these devices were not as good as expected. Because the surface of nitride-based epitaxial layers is defective in general, it is difficult to achieve high-quality Schottky contacts. As a result, gate leakage currents are often large in GaN-based MES-FETs, HFETs, and HEMTs. Gate leakage currents are much smaller in metal-insulator-semiconductor FETs ͑MIS-FETs͒ and MIS-HFETs. Previously, the fabrications of GaN-based MIS-FETs and MISHFETs using Si 3 N 4 , Ga 2 O 3 , Gd 2 O 3 , SiO 2 , MgO, Sc 2 O 3 , and stacked multilayer oxide as the insulating material have all been demonstrated. [5][6][7][8][9][10][11][12][13][14][15] Various techniques, such as plasma-enhanced chemical vapor deposition ͑PECVD͒, electron cyclotron resonance CVD ͑ECR-CVD͒, jet vapor deposition ͑JVD͒, low-pressure chemical vapor deposition ͑LPCVD͒, thermal oxidation, and photoelectrochemical oxidation ͑PEC͒ have all been used to deposit the insulator materials. 5-15 Photochemical vapor deposition ͑photo-CVD͒ system is another tool that can be used to grow high-quality insulators. [16][17][18][19][20][21] In using the photo-CVD system to grow thin films, it is important to select a proper light source with a radiation spectrum matching the absorption spectra of the reactant gases. Figure 1 shows a schematic diagram of our photo-CVD system with a 150 W water-cooled deuterium ͑D 2 ͒ lamp ͑Hamamatsu L1835͒ as the excitation source. This D 2 lamp emits strong UV and vacuum UV ͑VUV͒ light in the spectral region between 115 and 400 nm. Using such a system, we successfully fabricated Al/photo-CVD SiO 2 /GaN MI...

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“…15,16 Alternatively, the reduction of leakage current may also be achieved via the addition of an insulating gate layer by adopting a metal-insulatorsemiconductor ͑MIS͒ structure. 17,18 To our knowledge, lowtemperature ͑LT͒ GaAs layer has ever been attempted in GaAsbased field transistors for the purpose of reducing gate leakage. 19 For GaN-based devices, it has also been shown that one can significantly reduce the leakage current and achieve a much larger photocurrent to dark current contrast ratio by introducing a LT GaN on top of the conventional nitride UV PDs.…”

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confidence: 99%

High-Detectivity GaN MSM Photodetectors with Low-Temperature GaN Cap Layers and Ir∕Pt Contact Electrodes

Chang

et al. 2007

Electrochem. Solid-State Lett.

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GaN-based metal-semiconductor-metal ͑MSM͒ UV photodetectors ͑PDs͒ with a low-temperature ͑LT͒ GaN cap layer and Ir/Pt contact electrodes were fabricated. Compared with the conventional Ni/Au contacts, we found that Ir/Pt contacts can reduce the dark current. Further, a smaller dark current and larger UV-to-visible rejection ratio obtained from the PD with LT GaN cap layer and Ir/Pt contact electrodes were determined. Furthermore, the noise equivalent power and detectivity ͑D * ͒ were respectively obtained as 2.75 ϫ 10 −13 W and 1.76 ϫ 10 12 cm Hz 0.5 W −1 for the aforementioned PDs.

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Deposition of SiO₂ Layers on GaN by Photochemical Vapor Deposition

Cited by 29 publications

References 33 publications

AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

GaN MIS Capacitors with Photo-CVD SiN[sub x]O[sub y] Insulating Layers

High-Detectivity GaN MSM Photodetectors with Low-Temperature GaN Cap Layers and Ir∕Pt Contact Electrodes

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Deposition of SiO2 Layers on GaN by Photochemical Vapor Deposition

Cited by 29 publications

References 33 publications

AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

GaN MIS Capacitors with Photo-CVD SiN[sub x]O[sub y] Insulating Layers

High-Detectivity GaN MSM Photodetectors with Low-Temperature GaN Cap Layers and Ir∕Pt Contact Electrodes

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Deposition of SiO₂ Layers on GaN by Photochemical Vapor Deposition