Low Resistance Ohmic Contact on p-type GaN Grown by Plasma-Assisted Molecular Beam Epitaxy

1996 ◽  
Vol 423 ◽  
Author(s):  
Myung C. Yoo ◽  
J. W. Lee ◽  
J. M. Myoung ◽  
K. H. Shim ◽  
K. Kim
Keyword(s):  
Molecular Beam Epitaxy ◽  
Ohmic Contacts ◽  
Doping Concentration ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma ◽  
Specific Contact Resistance ◽  
Metal Bilayers ◽  
Auger Microscopy ◽  
P Type

AbstractOhmic contacts on p-type GaN have been investigated. High quality GaN epilayers on cplane sapphire were prepared using plasma-assisted molecular beam epitaxy that utilized an inductively coupled rf nitrogen plasma source and solid source beams. The resulting film thickness and the doping concentration of the grown samples were in the range of 0.7–1.35 μm and 1018 – 1020/cm3, respectively. The metallization consisted of high work function metal bilayers which included a combinations of 25 nm-thick Ni, Ti, Pt and/or Cr and 200 nm-thick Au on the highly p-doped GaN in a transmission line model pattern. Ohmic contacts were formed by alloying the bi-layers using rapid thermal annealing (RTA) at temperatures in the range of 300–700 °C for 1 min under nitrogen ambient. Current-voltage measurements showed that the specific contact resistance was as low as 1.2 × 10 −4 Ω–cm2 for the sample having 1.4 × 1020/cm3p-type doping concentration with a Cr/Au contact annealed at 500 °C for 1 min by RTA. Judging from the scanning Auger microscopy results and the glancing angle x-ray diffraction analysis, this resistance is attributed to Cr diffusion into the GaN layer.

p‐type CdSe grown by molecular beam epitaxy using a nitrogen plasma source

1994 ◽  
Vol 65 (4) ◽  
pp. 466-468 ◽  
Author(s):  
Takeo Ohtsuka ◽  
Junji Kawamata ◽  
Ziqiang Zhu ◽  
Takafumi Yao
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma ◽  
P Type

Study of Ohmic Contacts on P-Type ZnSe and ZnSe Epitaxial Layers Grown by Molecular Beam Epitaxy

1992 ◽  
Vol 281 ◽  
Author(s):  
C. Piskoti ◽  
B. Mykolajenko ◽  
M. Vaziri
Keyword(s):  
Molecular Beam Epitaxy ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Molecular Beam ◽  
Metal Contact ◽  
Epitaxial Layers ◽  
Preliminary Results ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
P Type

ABSTRACTTo study the formation of ohmic contacts, several metals have been deposited on p-types ZnTe and ZnSe epitaxial layers. The metals were deposited on the layers either by simple evaporation or by electroplating. The current-voltage characteristics associated with each metal contact were measured. The preliminary results of these measurements indicate that electroplating is a better technique for making ohmic contact to these layers.

Molecular beam epitaxy of p-type ZnSSe using a nitric oxide plasma source

1997 ◽  
Vol 15 (4) ◽  
pp. 2426-2427
Author(s):  
P. Uusimaa ◽  
K. Rakennus ◽  
A. Salokatve ◽  
M. Pessa ◽  
J. Likonen
Keyword(s):  
Nitric Oxide ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
P Type

P-type Mg-doped GaN grown by molecular beam epitaxy using ammonia as the nitrogen source

1995 ◽  
Vol 395 ◽  
Author(s):  
Z. Yang ◽  
L.K. Li ◽  
W.I. Wang
Keyword(s):  
Molecular Beam Epitaxy ◽  
Nitrogen Source ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Luminescent Properties ◽  
Nitrogen Plasma ◽  
Organic Chemical ◽  
Hole Density ◽  
P Type ◽  
Mg Doped

ABSTRACTThe electrical and luminescent properties of Mg-doped GaN films grown by molecular beam epitaxy (MBE) using ammonia as the nitrogen source have been investigated. Due to their different growth environments, the Mg-doped GaN films grown by MBE using ammonia exhibited properties that were different from similar films grown by metal-organic chemical vapor deposition (MOCVD). It has been found that the introduction of positive charges during growth is important in the achievement of p-type Mg-doped GaN grown by MBE using ammonia. With the introduction of a moderate nitrogen plasma, we have achieved p-type Mg-doped GaN films with a hole density of 4×1017 cm−3 and a mobility of 15 cm2/V-s at room temperature.

Heavyp‐doping of ZnTe by molecular beam epitaxy using a nitrogen plasma source

1993 ◽  
Vol 62 (8) ◽  
pp. 840-842 ◽  
Author(s):  
J. Han ◽  
T. S. Stavrinides ◽  
M. Kobayashi ◽  
R. L. Gunshor ◽  
M. M. Hagerott ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma

Ohmic Contacts to P-Type Epitexial and Imlanted 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 895-898 ◽  
Author(s):  
John Crofton ◽  
John R. Williams ◽  
A.V. Adedeji ◽  
James D. Scofield ◽  
S. Dhar ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Contact Resistance ◽  
Barrier Height ◽  
Ohmic Contacts ◽  
Doping Concentration ◽  
Theoretical Calculations ◽  
Specific Contact Resistance ◽  
Acceptor Doping ◽  
Specific Contact ◽  
P Type

Nickel ohmic contacts to p-type epitaxial and heavily implanted 4H-SiC are described. Room and elevated temperature results are presented. Elevated temperature measurements of specific contact resistance are compared to theoretical calculations. The calculations require the acceptor doping concentration and the contact’s barrier height. Epitaxial material has a known acceptor value thereby allowing the barrier height to be deduced by requiring agreement between the calculated and measured values of the contact resistance. Calculations of the contact resistance for implanted material use the barrier height from the epitaxial results along with a variable activated acceptor doping concentration which is adjusted to give agreement with measured room temperature specific contact resistances. Specific contact resistances as low as 7x10-6 ohm-cm2 fabricated on the Si face have been obtained to epitaxial 4H p-type material whereas contacts to implanted material result in much larger contact resistance values of 4x10-5 ohm-cm2. These results, when compared to theoretical calculations, indicate that activated acceptor doping concentrations in heavily implanted material are on the order of 2% of the implant concentration.

InNAs and GaInNAs self-assembled quantum dots and lasers grown by solid source molecular beam epitaxy

2003 ◽  
Vol 794 ◽  
Author(s):  
Z.Z. Sun ◽  
S.F. Yoon ◽  
K.C. Yew ◽  
B.X. Bo
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Quantum Dot ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma ◽  
Force Microscopy ◽  
Self Assembled ◽  
Dot Density

ABSTRACTSelf-assembled Ga1−xInxNyAs1-y quantum dots were grown on GaAs by solid source molecular beam epitaxy (SSMBE). Introduction of N was achieved by a RF Nitrogen plasma source. Formation of quantum dots by S-K growth mode is confirmed by observation of standard 2D-3D RHEED pattern transition. Atomic force microscopy (AFM) and photoluminescence (PL) measurements were used to characterize the structure and optical properties of GaInNAs quantum dots. High GaInNAs quantum dot density (1010∼1011cm−2) was obtained for different In and N composition (0.3≤ x ≤1, y≤0.01). The effect of surface coverage on dot density, dot size, and optical properties was studied in detail. Adjusting the bandgap confinement by incorporating a GaNAs strain-reduction layer into the GaInNAs dot layer was found to extend the emission wavelength by 170nm. Room temperature pulsed operation is demonstrated for a Ga0.5In0.5N0.01As0.99 quantum dot laser emitting at ∼1.1μm.

Some aspects of GaN growth on GaAs(100) substrates using molecular beam epitaxy with an RF activated nitrogen-plasma source

1995 ◽  
Vol 155 (3-4) ◽  
pp. 157-163 ◽  
Author(s):  
S.E. Hooper ◽  
C.T. Foxon ◽  
T.S. Cheng ◽  
L.C. Jenkins ◽  
D.E. Lacklison ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma

N- and P-Type Doping of ZnSe Using Gas Source Molecular Beam Epitaxy

1994 ◽  
Vol 340 ◽  
Author(s):  
P. A. Fisher ◽  
E. Ho ◽  
J. L. House ◽  
G. S. Petrich ◽  
L. A. Kolodziejski ◽  
...  
Keyword(s):  
Growth Rate ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Nitrogen Plasma ◽  
Gas Source ◽  
Excitonic Transition ◽  
N Incorporation ◽  
P Type ◽  
Donor Species

ABSTRACTHigh quality ZnSe:Cl has been grown on GaAs by gas source molecular beam epitaxy (GSMBE); elemental Zn and H2Se are used as source materials, with ZnCl2 as a dopant source for donors. Atomic Cl concentrations ([Cl]) approaching 1020 cm−3 have been incorporated into the lattice as indicated by secondary ion mass spectrometry (SIMS). At incorporation levels greater than 1020 cm−3, an appreciable decrease in the growth rate has been observed. The sharp transition to a negligible growth rate is attributed to the occurrence of a surface chemical reaction originating from Cl and H which are present in the GSMBE environment. For [Cl] as high as 4 x 1018 cm−3, the films exhibited high crystalline quality, as indicated by photoluminescence originating from a single intense donor-bound excitonic transition. Hydrogenation of semiconductors can potentially result in the electrical passivation of incorporated acceptor and donor species. In the case of ZnSe:Cl, H was present in the ZnSe layers, but did not appear to adversely affect the electrical properties of the n-type films. In contrast, for the growth of ZnSe:N, where a nitrogen plasma cell was employed as a source of nitrogen, the H concentration (as determined by SIMS) was observed to track the N concentration. The ZnSe:N films were highly resistive for various amounts of N incorporation, which suggests that H incorporation is an issue of primary importance in the p-type doping of ZnSe grown by GSMBE.

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