Characterization of selective reactive ion etching effects on delta-doped GaAs/AlGaAs MODFET layers

S. Agarwala, M. Tong, D. G. Ballegeer, K. Nummila, A. A. Ketterson, I. Adesida

Research output: Contribution to journalArticlepeer-review


The effects of selective reactive ion etching (SRIE) using SiCl4/SiF4 plasma on delta-doped GaAs/Al0.3Ga0.7As modulation-doped field-effect transistor (MODFET) structures and devices have been investigated. The results are compared with those of corresponding conventionally doped MODFETs. Hall measurements were conducted at 300 and 77 K to characterize the change in the transport properties of the two-dimensional electron gas due to low energy ion bombardment during the SRIE process. Delta-doped structures showed a smaller change in sheet carrier density and mobility compared to conventionally doped structures. Direct current and high frequency measurements were performed on the SRIE gate-recessed MODFETs. No significant change in threshold voltage was observed for the delta-doped MODFETs in contrast to an increase of about 300 mV for the conventionally doped MODFETs processed at a plasma self-bias voltage of -90 V and a 1200% overetch time. Maximum dc extrinsic transconductance and unity current gain cutoff frequency did not change with SRIE processing for either of the structures.

Original languageEnglish (US)
Pages (from-to)375-381
Number of pages7
JournalJournal of Electronic Materials
Issue number4
StatePublished - Apr 1993


  • Delta-doped MODFET
  • selective reactive ion etching

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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