An NMOS input merged bipolar/sidewall-MOS transistor with a bypass sidewall MOS transistor (NBiBMOS transistor)

The concept of merging a vertical n-p-n bipolar and two sidewall NMOS transistors into an NMOS input merged bipolar/sidewall-MOS transistor with a bypass sidewall NMOS transistor structure (NBiBMOS transistor) is described. The output current of this structure, unlike that of NBiMOS transistors, is significant even when the output voltage (V/sub CE/ or V/sub DE/) is less than the turn-on voltage of the n-p-n bipolar transistor (V/sub BE/= approximately 0.8 V). This structure, when used in BiCMOS logic gates, will allow the output voltage to swing all the way to 0.0 V rather than to 0.8 V. The feasibility of this concept was demonstrated by fabricating and DC characterizing the NBiBMOS transistor structures, which occupy approximately 1.2 times the area of a single n-p-n bipolar transistor. The NBiBMOS transistor has a higher drive capability than that of a structure consisting of an NBiMOS and a separate bypass transistor, because the body-source junction of the bypass NMOS transistor is forward biased.>