Effect of Reduced Extended Defect Density in MOCVD Grown AlGaN/GaN HEMTs on Native GaN Substrates

Anderson, Travis J.; Tadjer, Marko J.; Hite, Jennifer K.; Greenlee, Jordan D.; Koehler, Andrew D.; Hobart, Karl D.; Kub, Fritz J.

doi:10.1109/led.2015.2502221

Cited by 63 publications

(37 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The details of the device fabrication and as-fabricated electrical performance have been previously reported. 4 Strain and polarization at the GaN interface give rise to an internal piezoelectric field and a two dimensional electron gas (2DEG), by which carriers move from the source to the drain. Electron channeling contrast imaging (ECCO) was used on the as-grown films to estimate the threading dislocation densities (TDDs).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Editors' Choice—On the Radiation Tolerance of AlGaN/GaN HEMTs

Weaver

Anderson

Koehler

et al. 2016

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

The radiation tolerance of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on high quality, low threading dislocation density (TDD) ammonothermal GaN and hydride vapor phase epitaxy GaN substrates was studied and compared to the radiation response of devices on SiC substrates where the TDD is 10 4 times higher. Hall and transport measurements were performed as a function of 2 MeV proton fluence. The threading dislocation density had no effect on the radiation response. Comparing the results with published data reveals that almost all irradiated GaN-based HEMTs respond to radiation damage similarly regardless of differences in initial film quality, device structure, aluminum mole fraction, etc. AlGaAs/GaAs HEMTs are also shown to behave similarly but are around ten times more sensitive to radiation damage than GaN-based HEMTs. Known values of the displacement energy thresholds in GaN and GaAs are used to calculate that 36% fewer defects are created in GaN than in GaAs, which is too small to cause a 1000% difference in radiation sensitivity between GaN-and GaAs-based HEMTs. An alternative explanation is proposed in which the piezoelectric field at the AlGaN/GaN interface causes scattered carriers to be reinjected into the 2DEG channel, thereby mitigating some of the harmful radiation effects.

show abstract

mentioning

confidence: 99%

“…For comparison, the average value of TDD as stated in 2011 was ∼10 10 cm −2 , while in 2014 1 × 10 9 cm −2 was described as being high. 6 that vary by a factor of more than 10 4 . This suggests that the initial extended defect concentration in the GaN films is not a driving factor in determining the radiation response.…”

mentioning

confidence: 99%

Editors' Choice—On the Radiation Tolerance of AlGaN/GaN HEMTs

Weaver

Anderson

Koehler

et al. 2016

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The fundamental approach of using GaN/GaN substrates instead of GaN on foreign substrates did indeed indicate an improved electrical performance [16], as was also demonstrated by the authors in an earlier publication [17]. In this work, the electrical and thermal analyses are extended and supplemented with structural Transmission Electron Microscopy (TEM) analysis.…”

Section: Introductionmentioning

confidence: 59%

Low-Dispersion, High-Voltage, Low-Leakage GaN HEMTs on Native GaN Substrates

Alshahed

Heuken

Alomari

et al. 2018

IEEE Trans. Electron Devices

View full text Add to dashboard Cite

Abstract-In this work the advantages of GaN HEMTs grown on native GaN substrates over GaN/Si or GaN/Sapphire substrates are investigated, and correlated with epitaxial quality. TEM plane view and cross section analysis of GaN/GaN revealed dislocation density lower than 1 × 10 6 cm −2 , which is at least 3 orders of magnitude lower than the case of GaN/Si or GaN/Sapphire. In the case of GaN/Si, the dislocations did not necessarily originate from the substrate/nucleation layer interface, but the strain relief and isolation buffer stacks were main contributors to the dislocation density. GaN/GaN HEMTs demonstrated superior electrical and thermal performance. GaN/GaN demonstrated 3 orders of magnitude lower off-state leakage, current collapse (Ron increase) after stress bias less than 15% compared to 50% in the case of GaN/Si, and 2% drop of the onstate current due to self-heating in DC operation as compared to 13% and 16% for GaN/Si and GaN/Sapphire respectively. The GaN/Si thermal performance approached GaN/GaN only by substrate removal. Therefore GaN/GaN can allow high on-state current, low off-state leakage current, minimal current collapse, and enhanced thermal dissipation capability at the same time, which can be directly correlated to the absence of high dislocation densities.

show abstract

“…The difference in lattice mismatch and thermal expansion between GaN and Si cause a very high‐density threading dislocation in the epitaxial layer (dislocation density of approximately 10 9 cm −2 ). The effects of threading dislocation on the electrical characteristics of HEMT structures have been studied by using various substrates . Our previous research indicated that full width at half maximum (FWHM) of the X‐ray diffraction (XRD) of the AlN NL has a correlation with the VDBV of the HEMT structure on the Si substrate.…”

Section: Introductionmentioning

confidence: 99%

Impact of the AlN nucleation layer on the variation of the vertical-direction breakdown voltage of AlGaN/GaN high-electron-mobility transistor structures on a Si substrate

Yamaoka¹,

Kakamu

Ubukata³

et al. 2017

Phys. Status Solidi A

View full text Add to dashboard Cite

The growth conditions of the AlN nucleation layer (AlN NL) by focusing on the partial pressure of trimethyl aluminum (TMA) with a constant V/III ratio are optimized. The relationship between the size and the density of the surface pits of the AlN NL and the variation in the vertical‐direction breakdown voltage (VDBV) in the AlGaN/GaN high‐electron‐mobility transistor (HEMT) structure is determined. The maximum size of the pits in the surface of the AlN NL decreases as the partial pressure of TMA decreases. The density and the maximum size of the pits on the surface of the AlN NL decreased as the growth rate of AlN NL decreased. The pit density of the AlN NL decreases as the thickness of the AlN NL increased from 157 to 207 nm. Furthermore, the pit density is saturated when the thickness of the AlN NL was 207 nm. The optimum value of the thickness of AlN NL was about 200 nm. The variation in the VDBV of the HEMT structure decreases as the full width at half maximum (FWHM) of the rocking curve of the AlN (002) and AlN (102) planes, the pit density, and the maximum size of the pits in the AlN NL decrease. Thus, the variation in the VDBV of the HEMT structure can be related with the process of regrowth over the AlN NL.

show abstract

Effect of Reduced Extended Defect Density in MOCVD Grown AlGaN/GaN HEMTs on Native GaN Substrates

Cited by 63 publications

References 14 publications

Editors' Choice—On the Radiation Tolerance of AlGaN/GaN HEMTs

Editors' Choice—On the Radiation Tolerance of AlGaN/GaN HEMTs

Low-Dispersion, High-Voltage, Low-Leakage GaN HEMTs on Native GaN Substrates

Impact of the AlN nucleation layer on the variation of the vertical-direction breakdown voltage of AlGaN/GaN high-electron-mobility transistor structures on a Si substrate

Contact Info

Product

Resources

About