Enhancement of channel conductivity in AlGaN/GaN heterostructure field effect transistors by AlGaN:Si back barrier

Cho, E.; Brunner, F.; Zhytnytska, Rimma; Kotara, Przemyslaw; Würfl, Joachim; Weyers, M.

doi:10.1063/1.3634032

Cited by 15 publications

(15 citation statements)

References 17 publications

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“…The wider band gap associated with this layer causes an energy increase in the channel region under the gate. By combining a backbarrier structure with a recessed gate, normally-off operation was successfully achieved [13,14]. However, in this structure, the 2DEG density in the drift region is reduced, which increases the on-resistance.…”

Section: Normally-off Operationmentioning

confidence: 99%

Current status of GaN power devices

Kachi

2013

IEICE Electron. Express

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Abstract:The performance of GaN power devices has been rapidly improving. Recently, the main approach is the use of AlGaN/GaN HEMT structures on Si substrates, for which the target breakdown voltage is initially 600 V or less. Although issues still remain with regard to current collapse and the threshold voltage required for normallyoff operation, many companies have announced their intention to commercialize such devices. In this report, recent developments concerning GaN power devices are reviewed, and unresolved issues and future expectations are discussed.

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Section: Normally-off Operationmentioning

confidence: 99%

Current status of GaN power devices

Kachi

2013

IEICE Electron. Express

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“…22 In contrast, higher dislocation density promoted a higher proportion of deep C states compared to substitutional shallow acceptors. [24][25][26][27] One of the problems is the need to carefully optimize the C concentration: increasing the C density improves the breakdown voltage, but also enhances the frequency dispersion of parameters. 23 Carbon doping of GaN buffers has become a widely accepted technology for AlGaN/GaN HEMTs.…”

Section: Introductionmentioning

confidence: 99%

Temperature stability of high-resistivity GaN buffer layers grown by metalorganic chemical vapor deposition

Polyakov¹,

Smirnov²,

Кожухова³

et al. 2013

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Critical Mg doping on the blue-light emission in p -type GaN thin films grown by metal-organic chemical-vapor deposition J. Vac. Sci. Technol. A 21, 134 (2003); 10.1116/1.1524148 Electrical properties and defect states in undoped high-resistivity GaN films used in high-power rectifiers Nominally undoped GaN films were grown by metalorganic chemical vapor deposition under three different conditions, namely (1) "standard" growth conditions with growth temperature of 1000 C and growth rate of 1 lm/h, (2) slightly reduced growth temperature of 975 C, and (3) standard temperature, but higher growth rate of 2.5 lm/h. The standard sample had a net donor density <10 15 cm À3 , while the two other samples were semi-insulating, with sheet resistivity $10 14 X/square and the Fermi level pinned at E c À0.8 eV for the low temperature growth and at E c À0.9 eV for the high growth rate conditions. The photoconductivity spectra of both of these latter samples show the presence of centers with optical threshold near 1.35 eV commonly attributed to C interstitials and centers with optical threshold near 2.7-2.8 eV and 3 eV often associated with C-related defects. However, no signals that could be attributed to substitutional C acceptors and C donors were detected. Current relaxation spectroscopy revealed deep traps with activation energies 0.2, 0.25, 045, and 0.8 eV. Annealing at 800 C increased the concentration of these traps. The changes in resistivity induced by annealing in the high-growth rate sample were much stronger than for the low-temperature sample. The authors also observed a strong suppression of the yellow luminescence band intensity in the "standard" sample after annealing, as opposed to a slight increase of this band intensity in the two semi-insulating samples. The role of compensation by native defects and by deep levels related to carbon in the observed changes is discussed.

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“…The high‐frequency applications in power device improve by reduction in the parasitic capacitances . One of the ways to reduce the junction capacitances is increment in the width of the depletion region between the junctions.…”

Section: Resultsmentioning

confidence: 99%

An AlGaN/GaN HEMT by a reversed pyramidal channel layer: Investigation and fundamental physics

Jaghargh

Orouji

2020

Int J Numerical Modelling

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In this paper, an AlGaN/GaN HEMT with a reversed pyramidal channel layer (RPC‐HEMT) is proposed. The main purpose of the paper is an increase in the breakdown voltage of a conventional HEMT (C‐HEMT) to be suitable in high‐power applications. In the RPC‐HEMT, a reverse pyramidal channel layer in the high electric field traps the energetic carriers that cause the transistors to break. The steps decrease the carrier concentration across the two‐dimensional electron gas (2DEG) channel layer, especially under the gate contact. Therefore, the critical electrical field reduces by the uniform division of carrier mass and improves the breakdown voltage of the RPC‐HEMT by 32%. Besides, the maximum output power density of the new transistor improves compared with the conventional one. In addition, the radio frequency (RF) characteristics such as the cutoff frequency and maximum oscillation frequency of the RPC‐HEMT improve by the decline in the gate‐source capacitance. This article provides kink effects with the output reflection coefficient (S22) and the short‐circuit current gain (h21) to show how this anomalous phenomenon affects high‐frequency performance of devices. Finally, the proposed method makes the RPC‐HEMT appropriate for high‐power and high‐frequency applications.

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Enhancement of channel conductivity in AlGaN/GaN heterostructure field effect transistors by AlGaN:Si back barrier

Cited by 15 publications

References 17 publications

Current status of GaN power devices

Current status of GaN power devices

Temperature stability of high-resistivity GaN buffer layers grown by metalorganic chemical vapor deposition

An AlGaN/GaN HEMT by a reversed pyramidal channel layer: Investigation and fundamental physics

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