Miller´s approximation in VLSI and power bipolar transistors with reach-through collectors

Using a modified ionization model based on nonlocal impact ionization, Miller´s relationship is examined for typical reach-through collector VLSI bipolar transistors with collector epi-thickness between 0.025 and 1 μm. The empirical parameter n in Miller´s relationship is evaluated under nonlocal impact ionization conditions within the useful range of current gain which corresponds to 0.1>1-1/M>0.005. The validity of Miller´s relationship is also examined for power bipolar transistors having reach-through collectors (W_epi⩽W_pt) using local ionization model and design curves for the empirical parameter n are provided for different collector structures