Issues in developing ohmic contacts to GaN

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126433 ◽

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.

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Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154226 ◽

1989 ◽

Vol 47 ◽

pp. 450-451

Author(s):

S. Yegnasubramanian ◽

V.C. Kannan ◽

R. Dutto ◽

P.J. Sakach

Keyword(s):

High Performance ◽

Ohmic Contacts ◽

Surface Defects ◽

Pure Metal ◽

Device Fabrication ◽

Native Oxide ◽

Metal Thin Films ◽

Recent Developments ◽

Different Temperatures ◽

Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

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VERY LOW RESISTIVITY AuMn GATE OHMIC CONTACTS FOR GaInAs DIFFUSED JFETs

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1988496 ◽

1988 ◽

Vol 49 (C4) ◽

pp. C4-453-C4-456 ◽

Cited By ~ 3

Author(s):

P. E. HALLALI ◽

P. BLANCONNIER ◽

L. BRICARD ◽

J-C. RENAUD

Keyword(s):

Ohmic Contacts ◽

Low Resistivity

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TEM Studies and Contact Resistance of Au/Ni/Ti/Ta/n-GaN Ohmic Contacts

MRS Proceedings ◽

10.1557/proc-764-c3.17 ◽

2003 ◽

Vol 764 ◽

Cited By ~ 3

Author(s):

D.N. Zakharov ◽

Z. Liliental-Weber ◽

A. Motayed ◽

S.N. Mohammad

Keyword(s):

Contact Resistance ◽

Ohmic Contacts ◽

High Resolution Electron Microscopy ◽

X Ray ◽

Electron Energy Loss Spectrometry ◽

Resolution Electron ◽

Order Of Magnitude ◽

Contact Surfaces ◽

Electron Energy Loss ◽

Magnitude Difference

AbstractOhmic Ta/Ti/Ni/Au contacts to n-GaN have been studied using high resolution electron microscopy (HREM), energy dispersive X-ray spectrometry (EDX) and electron energy loss spectrometry (EELS). Two different samples were used: A - annealed at 7500C withcontact resistance 5×10-6 Ω cm2 and B-annealed at 7750C with contact resistance 6×10-5 Ω cm2. Both samples revealed extensive in- and out-diffusion between deposited layers with some consumption ofGaNlayerand formation of TixTa1-xN50 (0<x<25) at the GaN interface. Almost an order of magnitude difference in contact resistances can be attributed to structure and chemical bonding of Ti-O layers formed on the contact surfaces.

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Contacting Diffusion with FIB for Backside Circuit Edit—Procedures and Material Analysis

ISTFA 2005: Conference Proceedings from the 31st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2005p0064 ◽

2005 ◽

Author(s):

U. Kerst ◽

P. Sadewater ◽

R. Schlangen ◽

C. Boit ◽

R. Leihkauf ◽

...

Keyword(s):

Numerical Simulation ◽

Electrical Properties ◽

Process Parameters ◽

Thermal Effects ◽

Silicon Surface ◽

Ohmic Contacts ◽

Ion Beam ◽

Schottky Barriers ◽

Material Analysis ◽

Type Silicon

Abstract The feasibility of low-ohmic FIB contacts to silicon with a localized silicidation was presented at ISTFA 2004 [1]. We have systematically explored options in contacting diffusions with FIB metal depositions directly. A demonstration of a 200nm x 200nm contact on source/drain diffusion level is given. The remaining article focuses on the properties of FIB deposited contacts on differently doped n-type Silicon. After the ion beam assisted platinum deposition a silicide was formed using a forming current in two configurations. The electrical properties of the contacts are compared to furnace anneal standards. Parameters of Schottky-barriers and thermal effects of the formation current are studied with numerical simulation. TEM images and material analysis of the low ohmic contacts show a Pt-silicide formed on a silicon surface with no visible defects. The findings indicate which process parameters need a more detailed investigation in order to establish values for a practical process.

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Interfacial Structure of In/Pt/GaAs Heterojunction Ohmic Contacts.

10.21236/ada175102 ◽

1986 ◽

Author(s):

Dean C. Marvin ◽

Neil A. Ives ◽

Martin S. Leung

Keyword(s):

Ohmic Contacts ◽

Interfacial Structure

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КОМПЛЕКС БАЗОВЫХ ТЕХНОЛОГИЧЕСКИХ ПРОЦЕССОВ ДЛЯ ПОЛУЧЕНИЯ МОЩНЫХ ПОЛЕВЫХ ТРАНЗИСТОРОВ И МИС СВЧ-ДИАПАЗОНА НА ОСНОВЕ GAN И GAAS С ИСПОЛЬЗОВАНИЕМ ОТЕЧЕСТВЕННОГО ОБОРУДОВАНИЯ

Nanoindustry Russia ◽

10.22184/1993-8578.2020.13.3s.343.346 ◽

2020 ◽

Vol 96 (3s) ◽

pp. 343-346

Author(s):

А.Н. Алексеев ◽

С.И. Петров

Keyword(s):

Ohmic Contacts ◽

Field Effect Transistors ◽

Production Cycle ◽

Electronic Industry ◽

Plasma Chemical ◽

High Power Field ◽

Mbe Growth ◽

Technological Processes ◽

Plasma Chemical Etching ◽

Problems And Solutions

Представлены результаты разработки базовых технологических процессов, используемых при получении мощных полевых транзисторов и МИС СВЧ-диапазона на основе GaN и GaAs, таких как: выращивание гетероструктур методом МЛЭ, металлизация и отжиг омических контактов, травление мезаизоляции, затворная металлизация, пассивация диэлектриком и др. Обсуждаются основные проблемы и пути их решения, в том числе особенности технологических процессов глубокого плазмохимического травления для формирования сквозных металлизированных отверстий в SiC и GaAs. Отдельное внимание уделено вопросам обеспечения однородности и воспроизводимости и их влиянию на выход годных структур. Продемонстрированы результаты использования ряда технологических процессов в производственном цикле АО «Светлана-Рост» и других предприятий радиоэлектронной промышленности. The paper presents the results of the development of basic technological processes used in the production of microwave high-power field-effect transistors based on GaN and GaAs such as: MBE growth, metallization and annealing of ohmic contacts, etching of mesa insulation, gate metallization, passivation by dielectric etc. The main problems and solutions including features of technological processes of deep plasma-chemical etching in SiC and GaAs have been discussed. Special attention is paid to the issues of uniformity and reproducibility and their impact on the yield of structures. The results of the use of technological processes in the production cycle of Svetlana-Rost JSC and other enterprises of the radio-electronic industry have been demonstrated.

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