Induced changes in surface band bending of n-type and p-type AlGaN by oxidation and wet chemical treatments

Lin, Yow−Jon; Chu, Yow Lin; Lin, Wen Xiang; Chien, Feng-Tso; Lee, Chi Sen

doi:10.1063/1.2187397

Cited by 12 publications

(5 citation statements)

References 20 publications

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“…In this study, samples that were annealed at various temperatures were investigated to correlate changes in surface physical properties. Then, ultraviolet photoemission yield spectroscopy (UV-PEY) was adopted to determine the surface work functions of the samples and the surface state of the carriers [18]. Therefore, the experiment elucidated the relationship between the work functions and the sheet carrier densities.…”

Section: Introductionmentioning

confidence: 99%

Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

Chen

Tseng

Lin

2009

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

Chen

Tseng

Lin

2009

Journal of Crystal Growth

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“…The valence-band maximum (VBM) position was determined by the linear extrapolation of the leading edges of valence-band spectra. 28,29) In Fig. 4, we observe that the low binding energy cutoff of the ITO samples from group C or D shifts to a lower binding energy by 1.0 eV with respect to the low binding energy cutoff of the ITO samples from group A or B.…”

Section: Resultsmentioning

confidence: 89%

Effects of Sulfide Treatment of Indium Tin Oxide on Efficiency of Polymer Light-Emitting Diodes

Lin

Chou

Lin

et al. 2007

jjap

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The effects of the sulfide treatment of indium tin oxide (ITO) on the efficiency of polymer light-emitting diodes (PLEDs) were investigated in this study. We found that an increase in the work function of ITO and a decrease in the number of oxygen vacancies (VO) near the ITO surface region (due to the occupation of VO by sulfur) result in an increase in device efficiency. It is worth noting that a suitable sulfide treatment time is an important issue for producing high-external-quantum-efficiency PLEDs.

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“…The reduction of the surface states resulted in the reduction of the Ga dangling bonds and the passivation of the N vacancies by the formation of Ga-S bond on the GaNbased surface. 26,27 Figures 5 and 6 show the normalized noise power spectra ͑S I DS /I DS 2 ͒ as the function of the frequency of the untreated and the ͑NH 4 ͒ 2 S x -treated MOS-HEMTs measured in the linear region ͑V DS = 2 V and V GS = 2 to − 6 V͒. The noise spectral density ͑S I DS ͒ of the drain-source current ͑I DS ͒ was measured with an applied V DS bias voltage of 2 V at room temperature using a BTA 9812B noise analyzer, an HP 4145B semiconductor parameter analyzer, and an HP 35670A dynamic signal analyzer.…”

Section: Resultsmentioning

confidence: 99%

(NH[sub 4])[sub 2]S[sub x]-Treated AlGaN∕GaN MOS-HEMTs with ZnO Gate Dielectric Layer

Chiou

Lee

2011

J. Electrochem. Soc.

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The function of the ͑NH 4 ͒ 2 S x surface treatment on the AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors ͑MOS-HEMTs͒ was investigated by using the pulsed output characteristics and the low frequency noise measurements. The low carrier concentration and high resistivity 30-nm-thick ZnO film was deposited using the designed vapor cooling condensation system and utilized as the gate dielectric layer of the AlGaN/GaN MOS-HEMTs. The significant improvement of the pulsed output performance and low frequency noise behavior of the ͑NH 4 ͒ 2 S x -treated AlGaN/GaN MOS-HEMTs showed that the ͑NH 4 ͒ 2 S x surface treatment was an effective technique to reduce the surface state density and to obtain high quality interface between the ZnO gate dielectric layer and the AlGaN layer. The decrease of the surface states is attributed to the reduction of Ga dangling bonds and passivation of N vacancies by the formation of Ga-S bond on the AlGaN surface.In recent years, GaN-based semiconductors were successfully utilized in gas sensors, 1,2 electronic devices, 3,4 and optoelectronic devices 5,6 due to the inherent advantages including large and direct energy bandgap, high electron drift velocity, high breakdown field strength, and chemical stabilities. Because the two-dimensional electron gas of the AlGaN/GaN-based heterostrucure reveals high electron mobility, the metal-semiconductor high electron mobility transistors ͑MES-HEMTs͒ for use in high power and high frequency applications were reported previously. 7 However, the performance of the GaN-based MES-HEMTs inevitably suffered from the large gate leakage current and the high surface state density. The surface states on the GaN-based semiconductors surface resulted in the Fermi level pinning effect and the reduction of the Schottky barrier height. 8 To mitigate those drawbacks, passivation method of the high electron mobility transistors structure, which consist of inserting a dielectric layer between the gate metal and the GaN-based semiconductors, was developed. 9,10 Among them, the zinc oxide ͑ZnO͒-based semiconductors are promising candidates of the gate dielectric layer because the ZnO-and the GaN-based semiconductors possess the same wurtzite crystalline structure, nearly identical lattice constant, and bandgap energy. Furthermore, in view of the inherent properties including wide direct band ap ͑3.37 eV͒, large exciton binding energy ͑60 meV͒, and compatibility for wet etching process, ZnO-based semiconductors were used in various electronic and optoelectronic devices. 11-13 Although, several methods were used to deposit ZnO-based semiconductors onto various substrates, 14,15 ZnO usually exhibits n-type conductivity properties owing to the compensation effect of shallow donors induced by oxygen vacancies or zinc interstitials. 16,17 Recently, the vapor cooling condensation system was designed to deposit a high quality intrinsic ZnO ͑i-ZnO͒ film with low carrier concentration ͑7.6 ϫ 10 15 cm −3 ͒ and high resistivity. 18 In this work, the i-ZnO gat...

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Induced changes in surface band bending of n-type and p-type AlGaN by oxidation and wet chemical treatments

Cited by 12 publications

References 20 publications

Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

Effects of Sulfide Treatment of Indium Tin Oxide on Efficiency of Polymer Light-Emitting Diodes

(NH[sub 4])[sub 2]S[sub x]-Treated AlGaN∕GaN MOS-HEMTs with ZnO Gate Dielectric Layer

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