The 36 V Bipolar: $\beta \times V_{a} \times \text {fT} \times \text {BV} \times \text {JfT} \times$ Linearity Tradeoff

This paper reports on the optimization of a 36 V complimentary bipolar design by using a new depletion mode field-effect architecture for the collector of the bipolar that greatly expands the boundary of the familiar tradeoffs. This achieves an n-p-n with a measured |β at 1 V x V
_a
at 18 V| = |270 x 1100 V|, a JfT at 1 V = 28.7 μAμm
^-2
, and |fT at 1 V x BV| = |2.6 GHz x 58 V|, with a p-n-p having a |β at 1 V x V
_a
at 18 V| = |250 x 800 V|, a JfT at 1 V = 27.0 μ Aμm
^-2
, and |fT at 1 V x BV| = |1.9 GHz x 69 V|. While these performance enhancements appear to offer a lot with little expense, they do serve to reveal an additional tradeoff between β x V
_a
x fT x BV x JfT and Linearity. This is where the curvature of the forward output characteristic curves quantified by the extrapolated Early voltage significantly changes over the voltage range |0-10 V|. Through the use of measured silicon results with calibrated TCAD simulations, the physics behind this depletion mode collector design is explained, and using this understanding, it ultimately shows how it is possible to limit the range of the associated nonlinear performance for low collector biases. Then, keeping linearity as a key performance target together with the field-effect architecture, the 36 V bipolar is rebalanced to achieve ann-p-nwitha|β at 1 V x V
_a
at 18 V x fT at 1 V x JfT at 1 V x BV x Linearity| = |270 x 220 V x 2.6 GHz x 28.7 μAμm
^-2
x 47 V x (0.2-30 V) Linearity|, and a p-n-p with a |β at 1 V x V
_a
at 18 V x fT at 1 V x JfT at 1 V x BV x Linearity| = |185 x 180 V x 1.8 GHz x 27 μAμm
^-2
x 45 V x (0.2-30 V) Linearity|.