Entity

Time filter

Source Type

Kiev, Ukraine

Sachenko A.V.,Institute of Semiconductor Physics of Ukraine | Belyaev A.E.,Institute of Semiconductor Physics of Ukraine | Boltovets N.S.,Orion Research Institute | Brunkov P.N.,RAS Ioffe Physical - Technical Institute | And 9 more authors.
Semiconductors | Year: 2015

The temperature dependences of the contact resistivity (ρc) of ohmic contacts based on the Au-Ti-Pd-InN system are measured at an InN doping level of 2 × 1018 cm−3 in the temperature range of 4.2–300 K. At temperatures T > 150 K, linearly increasing dependences ρc(T) are obtained. The dependences are explained within the mechanism of thermionic current flow through metal shunts associated with dislocations. Good agreement between theoretical and experimental dependences is achieved assuming that the flowing current is limited by the total resistance of the metal shunts, and the density of conductive dislocations is ∼5 × 109 cm−2. Using the X-ray diffraction method, the density of screw and edge dislocations in the structure under study is measured: their total density exceeds 1010 cm−2. © 2015, Pleiades Publishing, Ltd. Source


Sachenko A.V.,Ukrainian Academy of Sciences | Belyaev A.E.,Ukrainian Academy of Sciences | Boltovets N.S.,Orion Research Institute | Zhilyaev Y.V.,RAS Ioffe Physical - Technical Institute | And 7 more authors.
Semiconductors | Year: 2013

The temperature dependences of the contact resistance ρc(T) of ohmic Pd-Ti-Pd-Au contacts to n-GaN and n-AlN wide-gap semiconductors with a high dislocation density are studied. The dependences ρc(T) for both contacts contain portions of exponential decrease ρc(T) and very weak dependence ρc(T) at higher temperatures. Furthermore, a plateau portion ρc(T) is observed in the low-temperature region for the Au-Pd-Ti-Pd-n-GaN contact. This portion appears only after rapid thermal annealing (RTA). In principle, the appearance of the plateau portion can be associated with preliminary heavy doping of the near-contact region with a shallow donor impurity and with doping during contact fabrication as a result of RTA, if the contact-forming layer contains a material that is a shallow donor in III-N. The dependences obtained are not explained by existing charge-transport mechanisms. Probable mechanisms explaining the experimental dependences ρc(T) for ohmic contacts to n-GaN and n-AlN are proposed. © 2013 Pleiades Publishing, Ltd. Source


Belyaev A.E.,Institute of Semiconductor Physics of Ukraine | Boltovets N.S.,Orion Research Institute | Vitusevich S.A.,Institute of Semiconductor Physics of Ukraine | Ivanov V.N.,Orion Research Institute | And 6 more authors.
Semiconductors | Year: 2010

The temperature dependences of the contact resistivity ρc of Au-TiBx Al-Ti-n+-n-n+-GaN-Al2O3 ohmic contacts have been studied before and after microwave treatment followed by nine-month room-temperature sample storage. The temperature dependences of ρc of initial samples were measured twice. The first measurement showed the temperature dependence typical of ohmic contacts; the repeated measurement in the temperature region above 270 K showed a ρc increase caused by metallic conductivity. After microwave treatment, the metallic conductivity in the ohmic contact is not observed. This is presumably associated with local heating of metal Ga inclusions under microwave irradiation and the formation, due to high chemical activity of liquid gallium, of compounds of it with other metallization components. In this case, the temperature dependence of ρc is controlled by ordinary charge transport mechanisms. After nine-month room-temperature storage, the temperature dependence of ρc is described by the tunneling mechanism of charge transport. © 2010 Pleiades Publishing, Ltd. Source


Sachenko A.V.,Institute of Semiconductor Physics of Ukraine | Belyaev A.E.,Institute of Semiconductor Physics of Ukraine | Pilipenko V.A.,Branch of the Scientific Technical Center Belmicrosystems of the Public Corporation | Petlitskaya T.V.,Branch of the Scientific Technical Center Belmicrosystems of the Public Corporation | And 6 more authors.
Semiconductors | Year: 2014

It is experimentally found that an ohmic contact based on Au-Pt-Ti-Pd-n +-Si metallization is formed due to nanoscale metal shunts containing Si, Au, and Pt in the region of the interface with n +-Si, which appears during heat treatment at T = 450°C for 10 min in a vacuum chamber with a residual pressure of 10-6 Torr. The high density of shunts adjoining dislocations and other imperfections is confirmed by the temperature dependence of the specific contact resistance ρc(T). The density of conductive dislocations, calculated from the temperature dependence of ρc is ∼5 × 109 cm-2 which correlates with the density of structural defects, determined by the etch pits after removal of the metallization layers. © 2014 Pleiades Publishing, Ltd. Source


Goncharuk N.M.,Orion Research Institute | Karushkin N.F.,Orion Research Institute | Orehovskiy V.A.,Orion Research Institute | Malyshko V.V.,Orion Research Institute
Telecommunications and Radio Engineering (English translation of Elektrosvyaz and Radiotekhnika) | Year: 2014

Operating frequency of the submillimeter wave diode based on AlGaN/GaN single-barrier nanostructure with non-resonance electron tunneling is determined by inertia of their barrier tunneling. In the present work, we aimed to increase operating frequency, so we considered analogical diode on AlGaAs/GaAs nanostructure, in which the effective electron mass and, hence, the inertia of their tunneling are less than in AlGaN/GaN one. We studied dependencies of negative conductance and a reactance of the diode on its diameter, transit angle, frequency and tunneling time. As the result, we determined the optimal values of diode diameter and transit angle that correspond to a maximal negative conductance of the diode with different tunneling time. We proved that operating frequency of gallium arsenide diode is half as large again than that of gallium nitride diode with equal parameters of a barrier layer. Furthermore, at equal tunneling time, maximal negative conductance of gallium arsenide diode is less than those for gallium nitride. © 2014 by Begell House, Inc. Source

Discover hidden collaborations