Temperature Effects in SmartSpice LEVEL=6 Ferroelectric Capacitance Model From Ramtron

Introduction

Implementation of a new ferroelectric capacitance model from Ramtron International Corporation into SmartSpice was first described in the April 2002 issue of SILVACO Simulation Standard. This model utilizes a new concept of double distribution of domain reversal voltages. The temperature effects were not detailed in the previous article. This application note discusses the implementation of the temperature effects and updates the device syntax.

Features

The updated ferroelectric model is invoked in SmartSpice by setting LEVEL=6 in the capacitance model card. This model differs from its predecessor (model FCAP LEVEL=5) in that the ferroelectric capacitor is regarded as a non-linear capacitor with Polarization-Voltage (P-V) hysteresis loop, however the biases in the ferroelectric materials are reversed at reversal voltages with double distributions. As compared with the LEVEL=5 model, the LEVEL=6 model demonstrates the following improvements: more accurate simulations of ferroelectric hysteresis loops and sub-loops, improved voltage pulse responses, faster simulation speed (up to six times faster), and added temperature dependence.