Abstract

In this work we first report on a theoretical model which provides the gate voltage dependence of the piezoelectric polarization charge in GaN HEMT devices. The model utilizes a generalization of Gauss' law, imposing constraints on the electric displacement vector D. The constraint on D is given by the continuity of the perpendicular component of the displacement vector across an interface. Poisson's equation is then solved across various layers under proper boundary conditions for the applied bias. The piezoelectric polarization charge is reduced due to the electromechanical coupling compared to the uncoupled case. Under high sheet electron densities, the correction in the piezoelectric polarization charge is also lower due to smaller electric fields. The theoretical model is then incorporated in the particle-based device simulator and device transfer and output characteristics are calculated without and with the bias dependent polarization charge. We find that percentage change in drain current increases with larger negative bias on the gate, due to the larger vertical electric fields.

Original languageEnglish (US)
Pages (from-to)592-597
Number of pages6
JournalMicroelectronics Journal
Volume44
Issue number7
DOIs
StatePublished - Jul 2013

Fingerprint

Electromechanical coupling
High electron mobility transistors
high electron mobility transistors
Polarization
degradation
Degradation
polarization
Electric fields
electric fields
Drain current
Poisson equation
continuity
simulators
Carrier concentration
Simulators
Boundary conditions
boundary conditions
output
Electric potential
electric potential

Keywords

  • Electro-mechanical coupling
  • GaN HEMTs
  • Piezoelectric polarization charge
  • Polarization charges

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Cite this

Current degradation due to electromechanical coupling in GaN HEMT's. / Padmanabhan, Balaji; Vasileska, Dragica; Goodnick, Stephen.

In: Microelectronics Journal, Vol. 44, No. 7, 07.2013, p. 592-597.

Research output: Contribution to journalArticle

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