The paper presents a novel PNP-type BJT-mode operated MOS structure that significantly pushes up the cut-off frequency limit, without necessarily employing submicron patterning. In order to reach the requested high speed, the base width (channel length) is rendered independent of processes minimum feature and the excess minority carriers charge in the extrinsic base is reduced using an insulation technique. Full bulk hole mobility is obtained by operating the MOS structure in 'purely BJT- mode'. The proposed device is fully compatible with standard recessed LOCOS single-polysilicon BiCMOS processes and offers a valid alternative to shallow polysilicon emitter vertical PNP-type transistors. Our CAD simulations yielded maximum cut-off frequencies of 2.45 GHz, 3.05 GHz and 5.65 GHz for 2 micrometers , 1 micrometers and 0.4 micrometers minimum feature structures, respectively.
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