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.

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.

scholarly journals Низкотемпературные омические контакты на основе Ta/Al к гетероэпитаксиальным структурам AlGaN/GaN на кремниевых подложках

2019 ◽  
Vol 53 (2) ◽  
pp. 249
Author(s):  
Е.В. Ерофеев ◽  
И.В. Федин ◽  
В.В. Федина ◽  
А.П. Фазлеев
Keyword(s):  
Low Temperature ◽  
Surface Morphology ◽  
Contact Resistance ◽  
Contact Area ◽  
Ohmic Contact ◽  
Smooth Surface ◽  
Ohmic Contacts ◽  
Nitrogen Atmosphere ◽  
Silicon Substrates ◽  
20 Nm

AbstractThe formation features of a low-temperature Ta/Al-based ohmic contact to Al_0.25Ga_0.75N/GaN heteroepitaxial structures on silicon substrates are studied. The fabricated ohmic contacts based on Ta/Al/Ti (10/300/20 nm) compositions have a low contact resistance (0.4 Ω mm) and smooth surface morphology of the contact area and its edge after 60-s annealing at T = 550°C in a nitrogen atmosphere.

Low Resistance Ti5Si3/TiC Ohmic contact on Ion-Implanted n-Type 4H-SiC C Face

2018 ◽  
Vol 924 ◽  
pp. 409-412
Author(s):  
Milantha de Silva ◽  
Teruhisa Kawasaki ◽  
Shinichiro Kuroki
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Laser Annealing ◽  
Specific Contact Resistance ◽  
High Concentration ◽  
Low Resistance ◽  
Impurity Doped ◽  
Activation Annealing ◽  
Ion Implanted

Low-resistance Ohmic contact on n+4H-SiC C-face with Titanium was demonstrated. In a conventional NiSi Ohmic contat on n-type 4H-SiC, a carbon agglomeration at the silicide/SiC interface occurs, and contact resistance becomes larger. For suppressing the carbon agglomeration, laser annealing and Ti metal were introduced to form both silicide and carbide. Ti (75 nm)/SiC and Ni (75 nm)/SiC Ohmic contacts were formed on backside C-face of high concentration impurity doped 4H-SiC substrates with and without activation annealing. Electrical properties were investigated after 40 nanoseconds pulse laser annealing in Ar ambient. As the result, the lowest specific contact resistance of 7.9×10-5Ωcm2was obtained in Ti (75 nm)/SiC sample in the case of ion implanted sample at 500°C and with activation annealing at a laser power of 2.2 J/cm2.

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.

Laser Processed Silicides for GaAs Hemts

1989 ◽  
Vol 158 ◽  
Author(s):  
W.T. Anderson ◽  
A. Christou ◽  
P.E. Thompson ◽  
J.L. Davis ◽  
C.R. Gossett ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Refractory Metal ◽  
Ohmic Contacts ◽  
Laser Annealing ◽  
Metal Silicide ◽  
Rf Power ◽  
Excimer Laser Annealing ◽  
Metal Gates ◽  
Sputter Deposited ◽  
Gate Resistance

ABSTRACTLaser annealed refractory metal gates and Ohmic contacts have been developed for GaAs FETs and HEMTs fabricated on MBE layers grown on laser desorbed substrates. Amorphous refractory metal silicide films were sputter deposited by a method in which the RF power to separate refractory metal and silicon targets were set at predetermined deposition ratesand the substrates were rotated with respect to the sputter targets receiving a 0.2 to 0.5 nm film on each pass. The gate resistance was reduced and Ohmic contacts formed by pulsed excimer laser annealing.

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).

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.

Excimer‐laser annealed ohmic contacts ton‐GaAs substrates through an ultrathin reacted layer

1987 ◽  
Vol 62 (6) ◽  
pp. 2381-2386 ◽  
Author(s):  
Syunji Imanaga ◽  
Hiroji Kawai ◽  
Kazuo Kajiwara ◽  
Kunio Kaneko ◽  
Naozo Watanabe
Keyword(s):  
Excimer Laser ◽  
Ohmic Contacts ◽  
Gaas Substrates
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