Pt3In7 Ohmic Contacts to n-TYPE GaAs

1992 ◽  
Vol 260 ◽  
Author(s):  
D. Swenson ◽  
Y. A. Chang
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Ohmic Behavior

ABSTRACTA thermodynamic and kinetic rationale was utilized to select Pt3In7 as an ohmic contact to n-GaAs. This analysis predicted that the contact metallurgy would be very simple and extremely uniform upon annealing. Preliminary electrical results showed that annealing samples at temperatures of 650 °C or higher led to ohmic behavior. A contact resistance of 3.4 × 10-5 Ω-cm2 was found upon annealing an uncapped contact at 750 °C for 15 s.

Au/Ge/Pd Ohmic Contacts to n-TYPE InP

1992 ◽  
Vol 260 ◽  
Author(s):  
Ping Jian ◽  
Douglas G. Ivey ◽  
Robert Bruce ◽  
Gordon Knight
Keyword(s):  
Thermal Stability ◽  
Contact Resistance ◽  
Transmission Line ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Changes ◽  
Ohmic Behavior ◽  
Quaternary Phase ◽  
Transmission Line Method ◽  
Ohmic Contact Formation

ABSTRACTOhmic contact formation and thermal stability in a Au/Ge/Pd metallization to n-type InP, doped to a level of 1017 cm-3, have been investigated. Contact resistance was measured using a transmission line method, while microstructural changes were examined by means of TEM, EDX, CBED and SAD. Contacts became ohmic after annealing at temperatures ranging from 300°C to 375°C. A minimum contact resistance of 2.5×l0-6 Ω-cm2 was obtained after annealing at 350°C for 320s. The drop in resistance to ohmic behavior corresponded to the decomposition of an epitaxial quaternary phase (Au-Ge-Pd-P). Annealing at 400°C and above resulted in Au10In3 spiking into InP and a break down of contact lateral uniformity, which increased contact resistance.

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

An Approach to Improving the Morphology and Reliability of n-SiC Ohmic Contacts to SiC Using Second-Metal Contacts

2006 ◽  
Vol 527-529 ◽  
pp. 859-862 ◽  
Author(s):  
Matthew H. Ervin ◽  
Kenneth A. Jones ◽  
Un Chul Lee ◽  
Taniya Das ◽  
M.C. Wood
Keyword(s):  
Electrical Properties ◽  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Chemical Properties ◽  
Physical Contact ◽  
Metal Contacts ◽  
Critical Feature ◽  
Excess Carbon ◽  
Ohmic Contact Formation

While nickel ohmic contacts to n-type silicon carbide have good electrical properties, the physical contact, and therefore the reliability, can be poor. An approach is described for using the good electrical properties of Ni ohmic contacts while using another metal for its desired mechanical, thermal and/or chemical properties. In the present work, once the Ni contacts have been annealed forming nickel silicides and achieving low contact resistance, they are etched off. Removing the primary Ni contacts also eliminates the poor morphology, voids, and at least some of the excess carbon produced by the Ni/SiC reaction. The Ni contacts are then replaced by a second contact metal. This second metal displays low contact resistance as-deposited, indicating that the critical feature responsible for the ohmic contact has not been removed by the primary contact etch. Not only does this approach provide more flexibility for optimizing the contact for a given application, it also provides some insight into the ohmic contact formation mechanism.

Ohmic Contact Resistance to GaN Devices Dependence with on Temperature for GaN Devices T

2011 ◽  
Vol 679-680 ◽  
pp. 816-819 ◽  
Author(s):  
Amador Pérez-Tomás ◽  
A. Fontserè ◽  
Marcel Placidi ◽  
N. Baron ◽  
Sébastien Chenot ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Temperature Dependence ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Schottky Diodes ◽  
Electron Gas ◽  
Temperature Measurements ◽  
Back Contact ◽  
Dimensional Electron ◽  
Dimensional Electron Gas

The temperature dependence of Ohmic contacts to GaN devices is investigated in this paper via by measuring TLM contact resistances TLM vs Tas a function of temperature. measurements. In particular, the two types of Ohmic contacts are considered: (1) Contacts to highly doped implanted regions (such as the MOSFET drain/source contacts or the back contact of Schottky diodes) and (2) contacts to the 2 dimensional electron gas (2DEG) of an AlGaN/GaN heterojunction.

Refinement of low-resistance Ni–Ge–Au ohmic contacts to n+ GaAs using screening and response surface experiments

1996 ◽  
Vol 11 (5) ◽  
pp. 1238-1243 ◽  
Author(s):  
Nancy E. Lumpkin ◽  
Warren King ◽  
T. L. Tansley
Keyword(s):  
Contact Resistance ◽  
Response Surface ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
High Electron Mobility Transistors ◽  
Process Variable ◽  
Fractional Factorial ◽  
Order Effects ◽  
High Electron ◽  
Screening Experiment

Multivariable screening and response surface experiments have been performed to model ohmic contact resistance (Rc) of a Ni–Ge–Au ohmic metal process for n+ GaAs-based high electron mobility transistors (HEMTs). Seven variables were examined via a fractional factorial screening experiment to rank the effects of each process variable. The results of the screening experiment indicated that the most significant variables were total Ge and Au evaporated thickness, Ge-to-Au ratio, and the post-alloy cooling time. Response surface experiments were designed around these three variables to examine the first- and second-order effects. The results enabled the development of an empirical model of ohmic contact resistance from which a new low value of 0.03 ± 0.03 Ω · mm (one-sigma) was predicted. Twenty confirmation runs on the new process indicated an average Rc of 0.06 ± 0.02 Ω · mm (one-sigma), with a range of 0.02 Ω · mm to 0.11 Ω · mm, a reduction from the previous average process value of 0.14 ± 0.07 Ω · mm (one-sigma).

Laser annealed ohmic contact to n+-GaAs

1983 ◽  
Vol 61 (8) ◽  
pp. 1218-1221 ◽  
Author(s):  
P. Sircar
Keyword(s):  
Surface Morphology ◽  
Contact Resistance ◽  
Excimer Laser ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Laser Annealing ◽  
Furnace Annealing ◽  
Gaas Substrates ◽  
Thin Nickel ◽  
Lower Contact

Ohmic contacts were made on n+-GaAs substrates by evaporating a gold–germanium eutectic film with or without a thin nickel overlayer and then alloying these samples either in a furnace or by means of an excimer laser. It is found that laser annealing gives a better surface morphology and a lower contact resistance than furnace annealing.

Dual Role of Tin Reaction Barrier in Gold-Based Metallization to GaAs

1993 ◽  
Vol 300 ◽  
Author(s):  
A. Piotrowska ◽  
E. Kaminska ◽  
M. Guziewicz ◽  
S. Kwiatkowski ◽  
A. Turos
Keyword(s):  
Magnetron Sputtering ◽  
Contact Resistance ◽  
Ohmic Contact ◽  
Diffusion Barrier ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Tin Films ◽  
Specific Contact ◽  
Tin Diffusion Barrier

ABSTRACTThe formation of ohmic contacts to p-GaAs based on Au-Zn system comprising a TiN diffusion barrier has been investigated using 2 MeV He+ RBS and the specific contact resistance measurements. It has been proved that TiN films deposited by reactive RF bias magnetron sputtering serves two purposes. First it suppresses the arsenic evaporation and thus confines the reaction between AuZn and GaAs. Second, it prevents intermixing between p-GaAs/Au(Zn) ohmic contact and an overlayer of Au.

scholarly journals Омические контакты к эпитаксиальным структурам CVD-алмаза с дельта-слоями бора

2019 ◽  
Vol 53 (10) ◽  
pp. 1386
Author(s):  
Е.А. Архипова ◽  
Е.В. Демидов ◽  
М.Н. Дроздов ◽  
С.А. Краев ◽  
В.И. Шашкин ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Diamond Film ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Current Flow ◽  
Cvd Diamond ◽  
Boron Doped ◽  
Heavily Doped ◽  
Test Cells

Various methods of the formation of ohmic contacts to CVD diamond epitaxial structures with boron doped delta layers (δ-layers) are investigated. In the first approach, an additional thin, heavily doped layer was formed on the surface of the diamond film, to which the ohmic contact was formed. Then, the surface p+-layer between the contact pads was etched out, so the current flow in the structure occurred only through the buried δ-layer. In the second approach, doped diamond was selectively grown in contact windows under the mask of metal after preliminary etching the undoped diamond layer (cap) to the δ-layer. In this case, the heavily doped p+-layer will form a contact to the δ-layer. These approaches are differs by conditions of applicability, the complexity of manufacturing technology, the value of contact resistance. So they can be used to solve tasks in which different quality of contacts is required, such as the formation of transistor structures or test cells for measuring electrophysical characteristics.

Formation of Ni/Pt/Au Ohmic Contacts to p-GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
Ja-Soon Jang ◽  
Hyo-Gun Kim ◽  
Kyung-Hyun Park ◽  
Chang-Sub Um ◽  
Il-Ki Han ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Chemical Vapor ◽  
Electron Beam Evaporation ◽  
Specific Contact Resistance ◽  
Metal Thin Films ◽  
Linear Behavior ◽  
Specific Contact ◽  
P Type

AbstractWe report a new Ni/Pt/Au (20/30/80 nm) metallization scheme to achieve a low ohmic contacts to p-type GaN with a carrier concentration of 9.4 × 1016 cm-3. A Mg-doped GaN layer (0.5 μm) was grown on (0001) sapphire substrate by metalorganic chemical vapor deposition (MOCVD). All metal thin films were deposited on the p-GaN layer in an electron-beam evaporation system. Samples were annealed by a rapid thermal annealing (RTA) process at a range of temperatures from 300 °C to 850 °C under a flowing Ar atmosphere. A circulartransmission line model (c-TLM) was employed to calculate the specific contact resistance, and current-voltage (I-V) data were measured with HP4155A. The Ni/Pt/Au contacts without the annealing process showed nearly rectifying characteristics. The ohmic contacts were formed on the samples annealed at 500 °C for 30 sec and the I-V data showed a linear behavior. The specific contact resistance was 2.1 × 10-2 Ωcm2. However with increasing the annealing temperature above 600 °C, ohmic contacts were again degraded. Auger electron spectroscopy (AES) depth profiles were used to investigate the interfacial reactions between the trilayer and GaN. AES results suggested that Pt plays a significant role in forming ohmic contact as an acceptor at the interface. Atomic force microscope (AFM) also showed that the samples with good ohmic contact have very smooth surface.

scholarly journals Circular test structures for determining the specific contact resistance of ohmic contacts

2017 ◽  
Vol 30 (3) ◽  
pp. 313-326 ◽  
Author(s):  
Anthony Holland ◽  
Yue Pan ◽  
Mohammad Alnassar ◽  
Stanley Luong
Keyword(s):  
Finite Element ◽  
Contact Resistance ◽  
Finite Element Modeling ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Wave Mechanics ◽  
Element Modeling ◽  
Specific Contact ◽  
Modeling Software

Though the transport of charge carriers across a metal-semiconductor ohmic interface is a complex process in the realm of electron wave mechanics, such an interface is practically characterised by its specific contact resistance. Error correction has been a major concern in regard to specific contact resistance test structures and investigations by finite element modeling demonstrate that test structures utilising circular contacts can be more reliable than those designed to have square shaped contacts as test contacts become necessarily smaller. Finite element modeling software NASTRAN can be used effectively for designing and modeling ohmic contact test structures and can be used to show that circular contacts are efficient in minimising error in determining specific contact resistance from such test structures. Full semiconductor modeling software is expensive and for ohmic contact investigations is not required when the approach used is to investigate test structures considering the ohmic interface as effectively resistive.

Sign in / Sign up

Export Citation Format

Share Document