High-frequency capacitance–voltage measurement of plasma-enhanced chemical-vapor-deposition-grown SiO2/n-GaN metal-insulator-semiconductor structures

Chen, P.; Wang, W.; Chua, Soo-Jin; Zheng, Yi

doi:10.1063/1.1418451

Cited by 46 publications

(25 citation statements)

References 7 publications

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“…On the basis of measured time constants for electron emission from interface traps, 10 this narrow range in energy was deemed to be the limit of validity for the Terman method given our measurement conditions. The interface state density found here agrees well with previous measurements for PECVD SiO 2 on n-GaN, 11 but is significantly higher than the value of Ͻ5.0ϫ10 10 cm Ϫ2 eV Ϫ1 quoted for optimized oxide/nitride/ oxide insulator stacks. 10 Figure 2 shows the experimental setup used to study the effects of strain on these MIS diodes.…”

Section: Methodssupporting

confidence: 81%

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Strittmatter

Beach

Picus

et al. 2003

Journal of Applied Physics

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We report on the use of metal-insulator-semiconductor ͑MIS͒ diodes, formed on n-GaN with SiO 2 , for capacitive strain sensing. These diodes, when subjected to static strain, were found to exhibit a steady-state change in capacitance. As a result, they can be used to detect strain with frequencies all the way down to dc. We formulate a model to explain the action of piezoelectricity in the diode and obtain excellent agreement with measurements. The model is then used to develop design criteria which optimize the sensitivity of the diode to detect strain. The sensitivity of the devices tested here rivals that of the best silicon piezoresistive sensors, but could attain nearly tenfold improvement with only minor design changes. Finally, we consider the effects of interface states on sensor performance and demonstrate how static strain sensing in GaN MIS diodes is enabled by the high quality of the oxide interface.

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Section: Methodssupporting

confidence: 81%

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Strittmatter

Beach

Picus

et al. 2003

Journal of Applied Physics

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“…Incorporation of an insulator into GaN-based transistors to make metal-oxide-semiconductor field-effect transistors ͑MOSFETs͒ or metal-insulator field-effect transistors ͑MISFETs͒ results in reduced gate leakage compared to metal-semiconductor field-effect transistors with a Schottky gate. To achieve such metal-insulator or metal-oxidesemiconductor structures, there have recently been studies of various insulators on GaN, including SiO 2 , [1][2][3][4][5][6][7][8] Si 3 N 4 , 3,8,9 AlN, [9][10][11][12] 15 These works have investigated the insulator/GaN interface through fabrication of MIS structures and have shown improved leakage characteristics by incorporating the insulators into MISFETs. An SiO 2 layer under the gate has been shown to reduce gate leakage current in AlGaN / GaN heterostructure field effect transistors ͑HFETs͒ by 6 orders of magnitude compared to that of a conventional HFET.…”

Section: Introductionmentioning

confidence: 99%

Rutile films grown by molecular beam epitaxy on GaN and AlGaN∕GaN

Hansen¹,

Vaithyanathan²,

Wu³

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Titanium dioxide ͑TiO 2 , with the rutile structure͒ was grown on ͑0001͒ oriented GaN and ͑0001͒ Al 0.33 Ga 0.67 N / GaN heterostructure field effect transistor ͑HFET͒ structures by molecular beam epitaxy. X-ray diffraction showed ͑100͒ TiO 2 ʈ ͑0001͒ GaN͑AlGaN͒ and ͓001͔ TiO 2 ʈ ͗1120͘ GaN͑AlGaN͒ with three rotational variants of the TiO 2 . Transmission electron microscopy of 50 nm thick TiO 2 films on GaN and AlGaN / GaN showed sharp interfaces with no intermixing or reaction between the oxide and semiconductor. The TiO 2 exhibited a columnar film microstructure with a lateral domain size of a few nanometers parallel to ͑101͒ TiO 2 and a few tens of nanometers parallel to ͑101͒ TiO 2 . Metal-oxide HFETs with 50 nm thick TiO 2 dielectric layers under the gate were processed and compared to HFETs without the TiO 2 dielectric layer. The transconductance of the HFETs with TiO 2 was 140 mS/ mm, approximately 20% less than HFETs with no dielecric, and the pinchoff voltages of the two stuctures were comparable. The dielectric constant of the TiO 2 was ϳ70. The gate leakage current of the HFETs with TiO 2 , ϳ4 ϫ 10 −6 mA/ mm at 50 V, was approximately 4 orders of magnitude lower than that of the HFETs with no dielectric. Band offset measurements were performed using x-ray photoelectron spectroscopy, and the valence band of the rutile TiO 2 and the GaN nearly line up.

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“…6,10,11 However, a metaloxide-semiconductor structure is preferred, as it provides a higher input impedance, larger gate voltage swings, and lower gate leakage currents. 12,13 Aluminum oxide (Al 2 O 3 ) is an excellent gate dielectric for IIInitride based devices due to its large bandgap (7∼9 eV), relatively high dielectric constant (∼9) and high thermal stability (up to 1000…”

mentioning

confidence: 99%

A Comparison of N-Polar () GaN Surface Preparations for the Atomic Layer Deposition of Al₂O₃

Wei

Hossain

Briggs

et al. 2014

ECS J. Solid State Sci. Technol.

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Nitrogen-polar gallium nitride offers several advantages over Ga-polar GaN for high frequency-high power electronic devices, but its processing has not been fully developed. Here we report on a systematic study of the effect of surface pretreatments on N-polar GaN for metal oxide semiconductor capacitors (MOSCAPs). Bulk n-type GaN (0001) substrates were prepared with a variety of treatments including: HF; HCl; base-piranha; H 2 plasma; and no pretreatment for comparison. Then 14nm thick Al 2 O 3 layers were deposited by atomic layer deposition (ALD). Both the original surfaces of GaN and ALD films were characterized by atomic force microscopy (AFM). MOSCAPs were fabricated and characterized by capacitance-voltage (C-V) and current voltage (I-V) measurements. The surface morphology and electrical performance was greatly affected by the pretreatments due to the reactive nature of N-polar GaN. The MOSCAP fabricated on GaN as-received with no additional preparation had the best performance including the smallest hysteresis (0.03V), lowest leakage current density (2.09 × 10 −8 A/cm 2 at +4V) and total trap density (2.47 × 10 10 cm −2 eV −1 ). This was correlated to the smoothest surface morphology (0.23 nm). The wide bandgap semiconductor gallium nitride (GaN) is of great interest not only for optoelectronic devices such as blue LEDs, 1 laser diodes, 2 and UV detectors, but also for highly efficient electronic devices operating at high frequency, temperature and power. After years of development, Ga-polar GaN based high electron mobility transistors (HEMTs) have been demonstrated with excellent performance and high RF output power.3,4 Increasing the maximum frequency by scaling down the GaN HEMT dimensions to reduce electron transit time, establishing control of the contact resistance and capacitive elements are critically important to prevent device delay times and to achieve the best possible device performance.5 Nitrogen-polar GaN has potential advantages over Ga-polar GaN for high-frequency applications due to its low contact resistance and a natural back barrier to improve electron confinement.6-8 For example, an extremely low contact resistance of 23 -μm was reported by Mishra et al. 9 To date, most of the N-polar GaN HEMT devices employ structures with a Schottky barrier as the gate contact. 6,10,11 However, a metaloxide-semiconductor structure is preferred, as it provides a higher input impedance, larger gate voltage swings, and lower gate leakage currents. 12,13 Aluminum oxide (Al 2 O 3 ) is an excellent gate dielectric for IIInitride based devices due to its large bandgap (7∼9 eV), relatively high dielectric constant (∼9) and high thermal stability (up to 1000• C). 14-20 Precise control of this dielectric's thickness is necessary to maintain the aspect ratio between the gate length and the oxide thickness for good high frequency performance. Atomic layer deposition (ALD) offers excellent thickness control for the deposition of such dielectrics, 21 but the initial condition of the substrate surface is crucia...

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High-frequency capacitance–voltage measurement of plasma-enhanced chemical-vapor-deposition-grown SiO2/n-GaN metal-insulator-semiconductor structures

Cited by 46 publications

References 7 publications

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Rutile films grown by molecular beam epitaxy on GaN and AlGaN∕GaN

A Comparison of N-Polar () GaN Surface Preparations for the Atomic Layer Deposition of Al₂O₃

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High-frequency capacitance–voltage measurement of plasma-enhanced chemical-vapor-deposition-grown SiO2/n-GaN metal-insulator-semiconductor structures

Cited by 46 publications

References 7 publications

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Rutile films grown by molecular beam epitaxy on GaN and AlGaN∕GaN

A Comparison of N-Polar () GaN Surface Preparations for the Atomic Layer Deposition of Al2O3

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A Comparison of N-Polar () GaN Surface Preparations for the Atomic Layer Deposition of Al₂O₃