AlGaAs/InGaAs pseudomorphic high electron mobility transistor using Pd/Ge ohmic contact

J. L. Lee, Y. T. Kim, J. W. Oh, B. T. Lee

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Microstructural reactions of a Pd/Ge contact to a AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) have been investigated, and the results have been used to interpret the changes of electrical properties of the PHEMT. In the as-deposited state, a ternary phase of PdxGaAs containing excess Ge atoms is formed at the interface of Pd/GaAs. When the ohmic metals deposited were annealed at 300°C, a PdGe compound was formed and its contact resistivity was decreased to 1.2 × 10-7 Ω·cm2. This is due to the preferential outdiffusion of Ga atoms to the PdGe during annealing, leaving Ga vacancies behind. Simultaneously, Ge atoms are indiffused to the GaAs and occupy the Ga vacancies, converting the interfacial GaAs layer into n+-GaAs. The low-temperature PdGe ohmic contact allows changing the sequence in the formation of source/drain and gate electrodes in the PHEMT process. The device performance was remarkably improved as the annealing temperature was increased or the contact resistivity was reduced. The PHEMTs with a gate length of 1.1μm, annealed at 300°C, exhibit maximum transconductance of 381 mS/mm.

Original languageEnglish
Pages (from-to)1188-1193
Number of pages6
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume40
Issue number3 A
Publication statusPublished - 2001 Mar 1

Fingerprint

Ohmic contacts
High electron mobility transistors
high electron mobility transistors
aluminum gallium arsenides
electric contacts
Atoms
Vacancies
Annealing
atoms
electrical resistivity
annealing
Transconductance
transconductance
Electric properties
electrical properties
Temperature
Electrodes
electrodes
Metals
metals

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

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title = "AlGaAs/InGaAs pseudomorphic high electron mobility transistor using Pd/Ge ohmic contact",
abstract = "Microstructural reactions of a Pd/Ge contact to a AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) have been investigated, and the results have been used to interpret the changes of electrical properties of the PHEMT. In the as-deposited state, a ternary phase of PdxGaAs containing excess Ge atoms is formed at the interface of Pd/GaAs. When the ohmic metals deposited were annealed at 300°C, a PdGe compound was formed and its contact resistivity was decreased to 1.2 × 10-7 Ω·cm2. This is due to the preferential outdiffusion of Ga atoms to the PdGe during annealing, leaving Ga vacancies behind. Simultaneously, Ge atoms are indiffused to the GaAs and occupy the Ga vacancies, converting the interfacial GaAs layer into n+-GaAs. The low-temperature PdGe ohmic contact allows changing the sequence in the formation of source/drain and gate electrodes in the PHEMT process. The device performance was remarkably improved as the annealing temperature was increased or the contact resistivity was reduced. The PHEMTs with a gate length of 1.1μm, annealed at 300°C, exhibit maximum transconductance of 381 mS/mm.",
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AlGaAs/InGaAs pseudomorphic high electron mobility transistor using Pd/Ge ohmic contact. / Lee, J. L.; Kim, Y. T.; Oh, J. W.; Lee, B. T.

In: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, Vol. 40, No. 3 A, 01.03.2001, p. 1188-1193.

Research output: Contribution to journalArticle

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T1 - AlGaAs/InGaAs pseudomorphic high electron mobility transistor using Pd/Ge ohmic contact

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AU - Kim, Y. T.

AU - Oh, J. W.

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N2 - Microstructural reactions of a Pd/Ge contact to a AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) have been investigated, and the results have been used to interpret the changes of electrical properties of the PHEMT. In the as-deposited state, a ternary phase of PdxGaAs containing excess Ge atoms is formed at the interface of Pd/GaAs. When the ohmic metals deposited were annealed at 300°C, a PdGe compound was formed and its contact resistivity was decreased to 1.2 × 10-7 Ω·cm2. This is due to the preferential outdiffusion of Ga atoms to the PdGe during annealing, leaving Ga vacancies behind. Simultaneously, Ge atoms are indiffused to the GaAs and occupy the Ga vacancies, converting the interfacial GaAs layer into n+-GaAs. The low-temperature PdGe ohmic contact allows changing the sequence in the formation of source/drain and gate electrodes in the PHEMT process. The device performance was remarkably improved as the annealing temperature was increased or the contact resistivity was reduced. The PHEMTs with a gate length of 1.1μm, annealed at 300°C, exhibit maximum transconductance of 381 mS/mm.

AB - Microstructural reactions of a Pd/Ge contact to a AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) have been investigated, and the results have been used to interpret the changes of electrical properties of the PHEMT. In the as-deposited state, a ternary phase of PdxGaAs containing excess Ge atoms is formed at the interface of Pd/GaAs. When the ohmic metals deposited were annealed at 300°C, a PdGe compound was formed and its contact resistivity was decreased to 1.2 × 10-7 Ω·cm2. This is due to the preferential outdiffusion of Ga atoms to the PdGe during annealing, leaving Ga vacancies behind. Simultaneously, Ge atoms are indiffused to the GaAs and occupy the Ga vacancies, converting the interfacial GaAs layer into n+-GaAs. The low-temperature PdGe ohmic contact allows changing the sequence in the formation of source/drain and gate electrodes in the PHEMT process. The device performance was remarkably improved as the annealing temperature was increased or the contact resistivity was reduced. The PHEMTs with a gate length of 1.1μm, annealed at 300°C, exhibit maximum transconductance of 381 mS/mm.

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