Collector design tradeoffs for low voltage applications of advanced bipolar transistors

Impact Ionization in Thin Silicon Diodes

“…The slow energy relaxation in the highly doped region is also observed in Monte Carlo studies of highly doped drain regions, see e.g., [8]. In order to calculate the generation rate, we define an effective electric field, proportional to the carrier energy, by (4) which is then used in place of the electrostatic field in the expressions for the generation rate from [9], with the same numerical values for the coefficients. This effective field approaches the true electric field for diodes wider than .…”

“…As cutoff frequencies have increased beyond 300 GHz [1], the associated breakdown voltages have shown a much weaker reduction than anticipated, even in scaled, very highly doped collector-base depletion layers. Impact ionization in such thin depletion layers is influenced by nonlocal effects [2]- [4], where the peak of the generation rate does not coincide with the maximum electric field. Here we present low-power optical measurements of avalanche multiplication in nearly ideally abrupt Si pin-diodes, resembling ideal thin collector diodes.…”

Realising wide bandgap P-SiC-emitter lateral heterojunction bipolar transistors with low collector–emitter offset voltage and high current gain: a novel proposal using numerical simulation

“…effect [19] in the dual bandgap emitter SiGe base lateral Schottky collector PNM HBT. The simulated I/V characteristics of a dual bandgap emitter SiGe base lateral Schottky collector PNM HBT and a dual bandgap emitter SiGe base PNP HBT are shown in Fig.…”

A new lateral PNM Schottky collector bipolar transistor (SCBT) on SOI for nonsaturating VLSI logic design

“…In our simulations using ATLAS [11], we have used suitable models for the bandgap narrowing, SRH and Auger recombination and the concentration and field dependent mobility. Breakdown voltage is calculated including nonlocal impact ionization [13]. For simulating the Schottky junction properties, standard thermionic emission model is used including the image force barrier lowering effects [14].…”

“…At I C = 10 04 A, the f T of the SCBT is 2 GHz while the comparable lateral PNP transistor has a negligible cut-off frequency at this current. In spite of a large collector doping used in the lateral PNP transistor, it is clear that base widening due to Kirk effect [13] limits its high-frequency performance, while the lateral SCBT does not suffer from this shortcoming because of the metal collector. The presence of the Schottky collector also has the added advantage that the SCBT will not suffer from storage charge effects when the transistor is in saturation.…”