Single step lithography for double-recessed gate pseudomorphic high electron mobility transistors

R. Grundbacher, I. Adesida, Y. C. Kao, A. A. Ketterson

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

An asymmetric double-recessed gate process achieved through a single lithography step and a combination of wet and dry etching techniques is presented. The double-recessed gate process is beneficial in the fabrication of InGaAs/AlGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMTs) because breakdown voltage is enhanced while surface effects on the drain side of the gate are minimized. In contrast to conventional processes that require two lithography steps, the current process requires only a single lithography step for the asymmetric placement of a T-gate in a wide recess trench. The process utilizes a four-layer resist of polymethylmethacrylate (PMMA) and P(MMA-MAA) exposed by electron beam lithography. Upon development of the resist, a wet selective etch (citric acid:H2O2) is used to define the wide recess trench and then a dry selective etch (SiCl4/SiF4) is used to recess a narrow trench (within the wide recess trench) in which the gate foot rests. This technique can achieve gate lengths of 0.15μm and drain-side wide recess dimensions from 0.15 to 0.55μm while the source-side recess width is kept at or below 0.15 μm. Device results show improved breakdown voltages and output conductance with only slight reduction in transconductance and drain current for the PHEMTs fabricated using the technique as compared to PHEMTs fabricated using a trilayer T-gate process.

Original languageEnglish
Pages (from-to)49-52
Number of pages4
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume15
Issue number1
Publication statusPublished - Jan 1997
Externally publishedYes

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recesses
High electron mobility transistors
high electron mobility transistors
Lithography
lithography
Electric breakdown
Dry etching
Electron beam lithography
Wet etching
Drain current
Citric acid
Transconductance
electrical faults
Fabrication
citric acid
transconductance
aluminum gallium arsenides
etching
electron beams
fabrication

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)
  • Surfaces and Interfaces
  • Engineering(all)

Cite this

Single step lithography for double-recessed gate pseudomorphic high electron mobility transistors. / Grundbacher, R.; Adesida, I.; Kao, Y. C.; Ketterson, A. A.

In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 15, No. 1, 01.1997, p. 49-52.

Research output: Contribution to journalArticle

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