PSP-SOI: A Surface Potential Based Compact Model of Partially Depleted SOI MOSFETs

Abstract

This paper reports recent progress on partially depleted (PD) SOI modeling using a surface potential based approach. The new model, called PSP-SOI, is formulated within the framework of the latest industry standard bulk MOSFET model PSP. In addition to its physics-based formulation and scalability inherited from PSP, PSP-SOI captures SOI specific effects by including a floating body simulation capability, a parasitic bipolar model, and self-heating. A nonlinear body resistance is included for modeling body-contacted SOI devices. The PSP-SOI model has been extensively tested on several PD/SOI technologies.

Compact modeling and simulation of PD-SOI MOSFETs: Current status and challenges

“…The distributed effect of the body resistance is an essential element that is needed to capture the BC history-effect correctly. In principle, the MOSFET can be partitioned into smaller segments along the width direction then connected in series [6], [24], but the cost is a significant penalty in simulation time. Alternatively, as demonstrated in Fig.…”

“…Figure 1 shows a typical circuit element topology for a PD-SOI transistor. This topology follows the BSIMSOI model [5] and another similar construction is given in [6] with an excellent overview. A key feature differentiating PD-SOI from conventional bulk models is that the parasitic currents that drive charge into and out of the isolated body region must be explicitly included: gate-tobody, source and drain junction diodes, Gate Induced Drain Leakage (GIDL), and impact ionization.…”

“…The most accurate body resistance consists of several parallel resistances (well and halo implants) and series resistances (distributed or segmented body resistance) [24] and it is desirable to capture the bias-dependence as well [6]. A switching event causes a strong capacitive coupling to the body potential even in BC devices, and this leads to the history-effect similar to the one present in a floating-body device, i.e., no body contact structure is completely ideal.…”

Surface-potential-based compact modeling of dynamically depleted SOI MOSFETs

“…To obtain such expressions, a new symmetric linearization method is developed specifically for DD-SOI MOSFETs. This allows us to formulate the model within the context of the PSP and PSP-SOI PD models [7,16,8] but with DD effects included. Hence the secondary effects can be adopted into the DD-SOI model as in [7,8].…”