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High-voltage GaN-on-silicon Schottky diodes

May 13, 2013
  |
Conference Paper
Author:
Timothy Boles
…
Published in:
CS ManTech 2013, 13-16 May 2013.
Topic:
electronics
R&D area:

Summary

M/A-COM Technology Solutions has continuing joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Laboratory to develop GaN-on-silicon two and three-terminal high-voltage/high current switching devices. The initial developmental goals were for a Schottky diode that has a reverse breakdown blocking voltage of >600 volts and is capable of handling 10 amperes of forward current. A comparison of the M/A-COM Technology Solutions lateral GaN Schottky diode on-resistance as a function of reverse breakdown voltage for a number of both lateral and vertical GaN Schottky diode geometries taken from the literature is presented. The substrates employed for all of these data points are either sapphire, SiC, silicon, and even one study which utilized single crystal GaN. Also included in this plot are theoretical limits for the basic materials typically used in GaN Schottky diode construction. It can be seen that the reverse breakdown results of approximately 1500 volts for M/A/-COM Technology Solutions lateral anode connected field GaN Schottky diodes on silicon substrates compare extremely favorably with the reported performance of the state-of-the-art devices, regardless of substrate material or design geometry.
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Summary

M/A-COM Technology Solutions has continuing joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Laboratory to develop GaN-on-silicon two and three-terminal high-voltage/high current switching devices. The initial developmental goals were for a Schottky diode that has a reverse breakdown blocking voltage of >600...

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High-voltage GaN-on-silicon Schottky diodes

High voltage GaN-on-silicon HEMT

May 1, 2013
  |
Journal Article
Author:
Timothy Boles
…
Published in:
Phys. Status Solidi C, Vol. 10, No. 5, May 2013, pp. 844-8.
Topic:
electronics
R&D area:

Summary

M/A-COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus amd MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has a reverse breakdown characteristic of >1200 V and is capable of switching 10 amperes of current. An average three terminal breakown of 1322 V was achieved on a single finger 250 um GaN on silicon HEMT device utilizing a source connected field plate with a 4.5 um drain region overlap. An individual device breakdown on a single finger 250 um GaN on silicon HEMT device with a SCFP of >1630 V was measured at a current of 250 uA (1mA/mm) - One of the highest yet reported for GaN on silicon in the industry.
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Summary

M/A-COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus amd MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has...

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High voltage GaN-on-silicon HEMT

Atomic layer deposition of Sc2O3 for passivating AlGaN/GaN high electron mobility transistor devices

December 3, 2012
  |
Journal Article
Author:
Xinwei Wang
…
Published in:
Appl. Phys. Lett., Vol. 101, No. 23, 3 December 2012, 232109.
Topic:
electronics
R&D area:

Summary

Polycrystalline, partially epitaxial Sc2O3 films were grown on AlGaN/GaN substrates by atomic layer deposition (ALD). With this ALD Sc2O3 film as the insulator layer, the Sc2O3/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors showed excellent electrical performance with a high Ion/Ioff ratio of over 108 and a low subthreshold slope of 75 mV/dec. The UV/NH4OH surface treatment on AlGaN/GaN prior to ALD was found to be critical for achieving these excellent figures. In addition, the Sc2O3 dielectric is found to be negatively charged, which facilitates the enhancement-mode operation. While bare Sc2O3 suffers from moisture degradation, depositing a moisture blocking layer of ALD Al2O3 can effectively eliminate this effect.
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Summary

Polycrystalline, partially epitaxial Sc2O3 films were grown on AlGaN/GaN substrates by atomic layer deposition (ALD). With this ALD Sc2O3 film as the insulator layer, the Sc2O3/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors showed excellent electrical performance with a high Ion/Ioff ratio of over 108 and a low subthreshold slope of 75...

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Atomic layer deposition of Sc2O3 for passivating AlGaN/GaN high electron mobility transistor devices

30 to 50 ns liquid-crystal optical switches

January 1, 2010
  |
Journal Article
Author:
Michael W. Geis
…
Published in:
Optics Express, Vol. 18, No. 18, 30 August 2010, pp. 1886-18893.
Topic:
optics
R&D area:
R&D group:

Summary

The optical switching time of twisted-nematic liquid-crystal cells using the liquid crystals, 5CB (C,H,,-Ph-Ph-CN), 50CB(C,Hw O-Ph-Ph-CN) and PCH5 (C,H,,-Cy-Ph-CN) have been characterized as a function of temperature, prebias voltage and switching voltage, V. The transition time from 90 % to 10 % transmission scales as V-1.9 and is limited to 30 to 50 ns by the liquid-crystal breakdown electric field, - 100 V I'm-I The time fi-om the initial switching voltage step to 90 % transmission, delay time, decreases with increasing prebias and switching voltage. For 5CB and 50CS the delay time approaches a constant value at higher electric fields, >10 V ~1Il,-1. Both the transition and delay times decrease with increasing temperature. The minimum transition time at temperatures a few degrees below the nematicisotropic temperature are 32, 32, and 44 ns and delay times are 44, 25 and 8 ns for 5CB, 50CB, and PCH5 respectively.
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Summary

The optical switching time of twisted-nematic liquid-crystal cells using the liquid crystals, 5CB (C,H,,-Ph-Ph-CN), 50CB(C,Hw O-Ph-Ph-CN) and PCH5 (C,H,,-Cy-Ph-CN) have been characterized as a function of temperature, prebias voltage and switching voltage, V. The transition time from 90 % to 10 % transmission scales as V-1.9 and is limited to...

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30 to 50 ns liquid-crystal optical switches

Orthodox etching of HVPE-grown GaN

July 15, 2007
  |
Journal Article
Author:
J. L. Weyher
…
Published in:
J. Crystal Growth, Vol. 305, No. 2, July 15, 2007, pp. 384-392 (Proc. of the 4th Int. Workshop on Bulk Nitride Semiconductors IV, 16-22 October 2006).
Topic:
microelectronics
R&D area:

Summary

Orthodox etching of HVPE-grown GaN in molten eutectic of KOH+NaOH (E etch) and in hot sulfuric and phosphoric acids (HH etch) is discussed in detail. Three size grades of pits are formed by the preferential E etching at the outcrops of threading dislocations on the Ga-polar surface of GaN. Using transmission electron microscopy (TEM) as the calibration tool, it is shown that the largest pits are formed on screw, intermediate on mixed and the smallest on edge dislocations. This sequence of size does not follow the sequence of the Burgers values (and thus the magnitude of the elastic energy) of corresponding dislocations. This discrepancy is explained taking into account the effect of decoration of dislocations, the degree of which is expected to be different depending on the lattice deformation around the dislocations, i.e. on the edge component of the Burgers vector. It is argued that the large scatter of optimal etching temperatures required for revealing all three types of dislocations in HVPE-grown samples from different sources also depends upon the energetic status of dislocations. The role of kinetics for reliability of etching in both etches is discussed and the way of optimization of the etching parameters is shown.
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Summary

Orthodox etching of HVPE-grown GaN in molten eutectic of KOH+NaOH (E etch) and in hot sulfuric and phosphoric acids (HH etch) is discussed in detail. Three size grades of pits are formed by the preferential E etching at the outcrops of threading dislocations on the Ga-polar surface of GaN. Using...

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Orthodox etching of HVPE-grown GaN

Optimized growth of lattice-matched In(x)Al(1-x)N/GaN heterostructures by molecular beam epitaxy

January 8, 2007
  |
Journal Article
Author:
S. Schmult
…
Published in:
Appl. Phys. Lett., Vol. 90, No. 2, 8 January 2007, pp. 021922-1 - 021922-3.
Topic:
semiconductor (CMOS)
R&D area:

Summary

The authors present a systematic study on the growth of the ternary compound In(x)Al(1-x)N by molecular beam epitaxy. This work concentrates on In mole fractions x around 0.17, as this composition is in-plane lattice matched to GaN. At a growth temperature of 540 degrees C, high quality material was obtained using a total metal to nitrogen flux ratio of ~1. Using these growth parameters, high quality GaN/InAlN superlattices were obtained without growth interruptions.
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Summary

The authors present a systematic study on the growth of the ternary compound In(x)Al(1-x)N by molecular beam epitaxy. This work concentrates on In mole fractions x around 0.17, as this composition is in-plane lattice matched to GaN. At a growth temperature of 540 degrees C, high quality material was obtained...

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Optimized growth of lattice-matched In(x)Al(1-x)N/GaN heterostructures by molecular beam epitaxy

Nitride-based UV Geiger-Mode avalanche photodiodes

December 7, 2005
  |
Conference Paper
Author:
Richard J. Molnar
Published in:
2005 Int. Semiconductor Device Research Symp., 7-9 December 2005.
Topic:
semiconductor (CMOS)
R&D area:

Summary

III-N materials currently enjoy a predominant role in the formation of solid-state light emitters for [lamda]
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Summary

III-N materials currently enjoy a predominant role in the formation of solid-state light emitters for [lamda]

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Nitride-based UV Geiger-Mode avalanche photodiodes
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