Anjan Chakravorty

A compact model for silicon germanium heterojunction bipolar transistor based on transient integral charge-control (TICC) relations is presented. Partitioning factors are extracted from the numerically simulated data. A thorough analysis based on the transient and AC results has been carried out for checking the suitability of the model. No convergence problem is observed in transient simulation. The model shows acceptable accuracy in the phase behavior from low frequency up to transit frequency.

The performance enhancement in strained-Si n-MOSFETs are evaluated as a function of temperature. Mobility modeling at low temperature is reported. SPICE parameters are extracted for strained-Si n-MOSFETs for the first time. © 2007 IEEE.

This paper presents a physics-based compact dc model for high voltage silicon on insulator lateral double diffused MOS (SOI-LDMOS) transistor, assuming uniform doping for the channel. It uses MM20 model for the channel and drift region under the thin gate oxide, and proposes a new model for the drift region under the field oxide. This model shows that the current at higher gate voltages in SOI-LDMOS, is limited by the velocity saturation in the drift region under the field oxide, which determines the device behavior in the quasi-saturation region. The model exhibits high level of accuracy over wide bias ranges. ©2009 IEEE.

A physics based model for the non-quasi-static (NQS) effects occurring in heterojunction bipolar transistors (HBTs) is presented. Following classical transistor theory, partitioned charge based (PCB) approach is extended to additionally model small-signal frequency-dependent (trans-) conductances. A new large-signal model is implemented in Verilog-A, and is tested for small-signal behavior. Results are compared with numerical device simulation, and its improvement is checked against the results obtained from PCB approach and widely used 2nd order LCR sub-circuit. ©2009 IEEE.

In this paper, analytical models of subthreshold current and slope for asymmetric four-terminal double-gate (DG) MOSFETs are presented. The models are used to study the subthreshold characteristics with asymmetry in gate oxide thickness, gate material work function, and gate voltage. A model for the subthreshold behavior of three-terminal DG MOSFETs is also presented. The results of the models show excellent match with simulations using MEDICI. The analytical models provide physical insight which is helpful for device design. © 2008 IEEE.

Three different noise models are investigated from physical perspective using hydro-dynamic device simulation of 1D SiGe-HBT. An intuitive noise model formulation is proposed based on the 1st and 2nd order charge partitioning across base-emitter and base-collector regions. It is verified that proposed model improves the modeling of base current noise and correlation between the base and collector current noise sources. ©2009 IEEE.