Properties of metamorphic materials and device structures on GaAs substrates

W. E. Hoke, T. D. Kennedy, A. Torabi, C. S. Whelan, P. F. Marsh, R. E. Leoni, S. M. Lardizabal, Y. Zhang, J. H. Jang, I. Adesida, C. Xu, K. C. Hsieh

Research output: Contribution to journalConference articlepeer-review


Metamorphic layer structures grown on GaAs substrates have been characterized and fabricated into high quality electrical and optical devices. The root mean square surface roughness of the metamorphic films is <15 Å, which is smaller than most device layer thicknesses. Cross-sectional transmission electron micrographs show that the dislocations necessarily formed during growth of the metamorphic buffer layer are predominantly contained in the buffer layer. Subsequently grown device layers exhibit planar interfaces. From plan view micrographs, the dislocation density is approximately 106cm-2 or less. The mobility of metamorphic high electron mobility transistor (HEMT) structures increases with indium content and is essentially equivalent to the mobility of the same structures grown lattice matched on InP substrates. The room temperature photoluminescence of transistor quantum wells is not degraded by growth on metamorphic buffer layers. High gain, low noise amplifiers have been demonstrated with long-term reliability. Metamorphic PIN photodiodes exhibit the same responsivities and bandwidths as InP PIN photodiodes. An integrated metamorphic PIN-HEMT layer structure has been grown. The responsivity of the PIN was 0.52 A/W with an unoptimized bandwidth approaching 30 GHz. The metamorphic high electron mobility transistor exhibited typical performance for current, transconductance, and pinch-off.

Original languageEnglish (US)
Pages (from-to)804-810
Number of pages7
JournalJournal of Crystal Growth
Issue number1-4
StatePublished - Apr 2003
EventProceedings of the Molecular Beam Epitaxy 2002 - San Francisco, CA, United States
Duration: Sep 15 2002Sep 20 2002


  • A1. Line defects
  • A3. Molecular beam epitaxy
  • B2. Semiconducting ternary materials
  • B3. High electron mobility transistors

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry


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