High-transconductance p-channel AlGaAs/GaAs HFETs with low-energyberyllium and fluorine co-implantation self-alignment |
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Authors: | Kiehl RA Hallali PE Yates J Tischler MA Potemski RM Cardone F |
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Affiliation: | IBM Thomas J. Watson Res. Center, Yorktown Heights, NY; |
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Abstract: | The fabrication and electrical characteristics of p-channel AlGaAs/GaAs heterostructure FETs with self-aligned p+ source-drain regions formed by low-energy co-implantation of Be and F are reported. The devices utilize a sidewall-assisted refractory gate process and are fabricated on an undoped AlGaAs/GaAs heterostructure grown by MOVPE. Compared with Be implantation alone, the co-implantation of F+ at 8 keV with 2×1014 ions/cm2 results in a 3× increase in the post-anneal Be concentration near the surface for a Be+ implantation at 15 keV with 4×1014 ions/cm2. Co-implantation permits a low source resistance to be obtained with shallow p+ source-drain regions. Although short-channel effects must be further reduced at small gate lengths, the electrical characteristics are otherwise excellent and show a 77-K transconductance as high as 207 mS/mm for a 0.5-μm gate length |
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