Interface Effects on Noise Temperature of Ungated GaAs-Mesfets
The noise behaviour of GaAs MESFETs depends on the microwave noise temperature of the epilayer [1, 2]. In order to investigate its dependence on:
four layers were suitably prepared and ungated GaAs FETs (channels) were fabricated on them. We measured the noise temperature of these devices at frequencies between 0.1 and 8 GHz. The measurements showed that the insertion of an undoped (buffer) layer between substrate and epilayer improves the noise behaviour of the epilayer in the MHz and GHz range. Etching the substrate surface before the epitaxial process also improves the noise temperature of the active layer with and without an inserted buffer layer.
the quality of the interface between active layer and substrate; and
the substrate preparation before the epitaxial process,
KeywordsSubstrate Surface Buffer Layer Active Layer Noise Temperature Saturation Current
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© M.K. Ahmed and H. Beneking 1980