A homogeneous and reproducible large-area, low dispersion GaN-on-Si normally-off 600 V transistor technology using selective GaN etching

2018 ◽  
Author(s):  
Patrick Waltereit ◽  
Marina Preschle ◽  
Stefan Muller ◽  
Lutz Kirste ◽  
Heiko Czap ◽  
...  
Keyword(s):  
Large Area ◽  
Gan On Si ◽  
Gan Etching ◽  
Low Dispersion

Large-Area, Device Quality GaN on Si Using a Novel Transition Layer Scheme

2002 ◽  
Vol 743 ◽  
Author(s):  
Pradeep Rajagopal ◽  
Thomas Gehrke ◽  
John C. Roberts ◽  
J. D. Brown ◽  
T. Warren Weeks ◽  
...  
Keyword(s):  
Transition Layer ◽  
Continuous Wave ◽  
Lattice Mismatch ◽  
Heteroepitaxial Growth ◽  
Large Area ◽  
High Quality ◽  
Industry Growth ◽  
Power Added Efficiency ◽  
Dimensional Electron Gas ◽  
Gan On Si

ABSTRACTThe emergence of III-nitride technology and fabrication of high quality GaN based devices is possible due to the advances in the heteroepitaxial growth of III-N thin-films on lattice-mismatched substrates. Typically, the substrate of choice is either SiC or sapphire. We have adopted 100mm Si as our substrate of choice; uniform substrates of high quality are inexpensive and plentiful due to decades of use in the microelectronics industry. Growth of device quality GaN on Si is challenged by the ∼17% lattice mismatch and an additional thermal expansion coefficient (TEC) mismatch of ∼56%. In order to accommodate this strain and TEC mismatch between Si and GaN, a novel transition layer was designed, grown and successfully optimized, ® obviating the need for either a PENDEO based overgrowth process or a SiC interlayer-based process. This growth technique (SIGANTIC®) does not require any wafer conditioning prior to growth and thus reduces the process complexity and maintains the cost effectiveness of the GaN on Si strategy. We will report on this manufacturable 100mm MOCVD heteroepitaxial process that consistently produces device quality AlGaN/GaN heterostructures with two dimensional electron gas (2DEG) mobilities typically around 1400 cm2/Vs at room temperature. Structural and electrical properties as determined by optical reflectance, atomic force microscopy, capacitance-voltage and van der Pauw Hall measurements, which are measured across the 100mm wafer, will be presented. Device results will be mentioned to show continuous wave (CW) RF operation at 2 GHz with competitive power output, gain and power added efficiency (PAE).

Crack-free III-nitride structures (> 3.5 μm) on silicon

2011 ◽  
Vol 1324 ◽  
Author(s):  
Mihir Tungare ◽  
Jeffrey M. Leathersich ◽  
Neeraj Tripathi ◽  
Puneet Suvarna ◽  
Fatemeh (Shadi) Shahedipour-Sandvik ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
High Electron Mobility Transistor ◽  
Poor Quality ◽  
Organic Chemical ◽  
High Electron ◽  
Large Area ◽  
Si Substrates ◽  
Substrate Engineering ◽  
Gan On Si

ABSTRACTIII-nitride structures on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. High voltage, high power density, and high frequency attributes of GaN make the III-N on Si platform the most promising technology for next-generation power devices. However, the large lattice and thermal mismatch between GaN and Si (111) introduces a large density of dislocations and cracks in the epilayer. Cracking occurs along three equivalent {1−100} planes which limits the useable device area. Hence, efforts to obtain crack-free GaN on Si have been put forth with the most commonly reported technique being the insertion of low temperature (LT) AlN interlayers. However, these layers tend to further degrade the quality of the devices due to the poor quality of films grown at a lower temperature using metal organic chemical vapor deposition (MOCVD). Our substrate engineering technique shows a considerable improvement in the quality of 2 μm thick GaN on Si (111), with a simultaneous decrease in dislocations and cracks. Dislocation reduction by an order of magnitude and crack separation of > 1 mm has been achieved. Here we combine our method with step-graded AlGaN layers and LT AlN interlayers to obtain crack-free structures greater than 3.5 μm on 2” Si (111) substrates. A comparison of these film stacks before and after substrate engineering is done using atomic force microscopy (AFM) and optical microscopy. High electron mobility transistor (HEMT) devices developed on a systematic set of samples are tested to understand the effects of our technique in combination with crack reduction techniques. Although there is degradation in the quality upon the insertion of LT AlN interlayers, this degradation is less prominent in the stack grown on the engineered substrates. Also, this methodology enables a crack-free surface with the capability of growing thicker layers.

scholarly journals Parametric Study of Compound Semiconductor Etching Utilizing Inductively Coupled Plasma Source

1996 ◽  
Vol 421 ◽  
Author(s):  
C. Constantine ◽  
D. Johnson ◽  
C. Barratt ◽  
R. J. Shul ◽  
G. B. Mcclellan ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Inductively Coupled Plasma ◽  
Electron Cyclotron Resonance ◽  
Plasma Source ◽  
Large Area ◽  
Inductively Coupled ◽  
Semiconductor Etching ◽  
Deposition Processes ◽  
Gan Etching ◽  
Very High

AbstractInductively Coupled Plasma (ICP) sources are extremely promising for large-area, highion density etching or deposition processes. In this review we compare results for GaAs and GaN etching with both ICP and Electron Cyclotron Resonance (ECR) sources on the same singlewafer platform. The ICP is shown to be capable of very high rates with excellent anisotropy for fabrication of GaAs vias or deep mesas in GaAs or GaN waveguide structures.

Fabrication of Large-Area Suspended MEMS Structures Using GaN-on-Si Platform

2009 ◽  
Vol 30 (10) ◽  
pp. 1045-1047 ◽  
Author(s):  
Jianan Lv ◽  
Zhenchuan Yang ◽  
Guizhen Yan ◽  
Wenkui Lin ◽  
Yong Cai ◽  
...  
Keyword(s):  
Large Area ◽  
Gan On Si

Large-Area Lateral AlGaN/GaN-on-Si Field-Effect Rectifier with Low Turn-On Voltage

2020 ◽  
pp. 1-1
Author(s):  
Michael Basler ◽  
Richard Reiner ◽  
Stefan Moench ◽  
Patrick Waltereit ◽  
Rudiger Quay ◽  
...  
Keyword(s):  
Field Effect ◽  
Large Area ◽  
Turn On ◽  
Gan On Si

scholarly journals Study of a homogeneous X-ray selected AGN sample

2013 ◽  
Vol 9 (S304) ◽  
pp. 161-163 ◽  
Author(s):  
Gurgen M. Paronyan ◽  
Areg M. Mickaelian ◽  
Hayk V. Abrahamyan
Keyword(s):  
Large Area ◽  
Optical Identification ◽  
X Ray ◽  
Photon Count ◽  
Radiation Fluxes ◽  
Different Types ◽  
Absolute Magnitudes ◽  
Optical Identifications ◽  
Low Dispersion ◽  
Bright Source

AbstractBased on optical identifications of ROSAT sources, we have created a large homogeneous catalog of X-ray selected AGN. The Hamburg-RASS Catalog (HRC) and Byurakan-Hamburg-RASS Catalog (BHRC) made up on the basis of optical identification of X-ray sources from ROSAT Bright Source (BSC) and Faint Source (FSC) catalogues, respectively, have been used. These identiifcations were based on low-dispersion spectra of Hamburg Quasar Survey (HQS). As a result, a new large sample of X-ray selected AGN has been compiled containing 4253 sources with photon count rate CR > 0.04 ct/s in the area with galactic latitudes |b|>20 and declinations δ>0. All these sources are classified as AGN or candidate AGN. We have carried out multiwavelength studies in several wavelength ranges (X-ray, optical, radio). Catalogues that more or less guarantee the completeness condition (all-sky or large area surveys) were used. A number of erroneous classifications were found (some AGN had been classified as stars or galaxies); 1024 and 59 from HRC and BHRC, respectively. Out of 4253 sources, 3352 are spectroscopically confirmed AGN (given in Veron-Cetty & Veron and Roma Blazar catalogs), and the rest 901 are candidate AGN. For 210 of them spectra are available in SDSS DR9, and the results of their classification are given in another paper. We calculated absolute magnitudes, fluxes, improved coordinates and redshifts. An attempt is made to find a connection between the radiation fluxes in different bands for different types of sources, and identify their typical characteristics, thus confirming candidate AGN and in some cases finding new ones.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

TEM Study of a Tilt Boundary in Hot-Pressed Silicon

1981 ◽  
Vol 39 ◽  
pp. 160-161
Author(s):  
C. B. Carter ◽  
J. Rose ◽  
D. G. Ast
Keyword(s):  
Electron Diffraction ◽  
Imaging Technique ◽  
Interface Structure ◽  
Large Area ◽  
Weak Beam ◽  
Lattice Fringe ◽  
Electron Diffraction Technique ◽  
Tilt Boundaries ◽  
Beam Technique ◽  
Twist Boundaries

The hot-pressing technique which has been successfully used to manufacture twist boundaries in silicon has now been used to form tilt boundaries in this material. In the present study, weak-beam imaging, lattice-fringe imaging and electron diffraction techniques have been combined to identify different features of the interface structure. The weak-beam technique gives an overall picture of the geometry of the boundary and in particular allows steps in the plane of the boundary which are normal to the dislocation lines to be identified. It also allows pockets of amorphous SiO2 remaining in the interface to be recognized. The lattice-fringe imaging technique allows the boundary plane parallel to the dislocation to be identified. Finally the electron diffraction technique allows the periodic structure of the boundary to be evaluated over a large area - this is particularly valuable when the dislocations are closely spaced - and can also provide information on the structural width of the interface.

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