Elimination of drain I/V collapse in MODFETs through the use of thin n-GaAs/AlGaAs superlattice |
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Authors: | Fischer R Masselink WT Klem J Henderson T Morko? H |
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Affiliation: | University of Illinois, Urbana, USA; |
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Abstract: | We report on the elimination of collapse of drain I/V characteristics in modulation-doped field-effect transistors at 77 K by replacing the doped AlGaAs with a thin GaAs/AlGaAs superlattice where only the GaAs is doped. Such thin barriers (10 ?/15 ?) are transparent to the electrons making the electron transfer into the bulk GaAs (undoped) possible. Room-temperature transconductances of 180 mS/mm which increased to 210 mS/mm at 77 K under both dark and light conditions were obtained. Furthermore, the threshold voltage of these devices did not shift appreciably on cooling (+0.12 V), and no noticeable light sensitivity at 77 K was observed for this device structure. |
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