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We examine the feasibility of developing bipolar transistors with current-gain and power-gain cutoff frequencies of 1-3 THz. High bandwidths are obtained by scaling; the critical limits to such scaling are the requirements that the current density increase in proportion to the square of bandwidth and that the metal-semiconductor contact resistivities vary as the inverse square of device bandwidth. Transistors with 755 GHz fmax and 324 GHz amplifiers have been demonstrated. Contacts with resistivity sufficient for the 64 nm scaling generation (1 THz ftau2 THz fmax) have been developed.