1. CADENCE CONFIDENTIAL Hicum Model in Spectre Diana Moncoqut, R&D manager June 4, 2004

2. CMI (Compiled Model Interface) A flexible and efficient low-level C-language interface A common model interface to Spectre,SpectreRF, AMS, UltraSim. Used to implement all kind of devices in the simulators: Transistors: Bsim3v3, Bsim4, Hicum, Mextram, Vbic,.. Passive Devices: Resistor, Capacitor, Inductor, Core, Port.. Used by customers to introduce their proprietary models to Spectre.

3. Implementation in Spectre First implementation was done by Conexant using CMI in 1999 Minor enhancements made by Cadence Update to version 2.1 in 2001 made by Cadence Enhancements suggested by ST to the substrate current Itss: –Itss(T) = Itss(T0) * (T/T0)^(3/Msf) * exp(VGB/(Msf*Vt) * (T/T0-1))) –Tef0 constant change from 0.01 to 1e-6 Temperature Implementation is now complete in Spectre/RF

4. Hicum model advantages A physically based-model Hicum model is the only model that accurately describes the minority charge and transit time Hicum model also gives a very accurate and robust large signal simulation

5. Hicum model status in Spectre  Diffusion capacitances are a simplified representation of the distributed minority charge in the transistor  C_de/C_dc are not exact derivatives of Q_de/Q_dc  This causes convergence problems in transient analysis Provided a work-around for this problem, and working on a complete solution in Q3. Any remaining problems in derivatives will be examined and fixed in Q3.

6. Hidden state problem in RF simulation Hidden-state problem A hidden state is a variable whose value is used before it is set, which means that its value is retained from a previous time point. In shooting-Newton, one must be able to access and manipulate the state of the circuit, one must be able to compute the sensitivity of v(t) with respect to v(0) Hidden states are a problem for any RF simulator based on PSS algorithms.

7. Hicum model status in Spectre In Hicum, Excess phase (  Qf,  iT ) is implemented using a second-order Bessel polynomial which introduces hidden states. For PSS to converge, we must « expose » the states by explicitely adding new signals in the system. Excess Phase Problems are solved in Spectre/RF by exposing the hidden states Exponential limiting. Dexp is used but EXP_MAX and EXP_MIN are not defined. Exponential limiting and PnJ limiting are added to Spectre/RF

8. Status of Customer Pcrs on the Hicum model Pcr NumberTitleCompanyRelease 700128Spectre convergence with hicum model (fixed by R&D) ST5.0.33_USR3* (9/04) 706545Spectre transient analysis problem with hicum model ST5.0.33.500.1.14& 4.4.6 ISR 138 689486Hicum simulation results changed between IC500MSR3 & IC5033 ST5.0.33.500.1.10 604766Hicum primitive enhancementST5.0.33_USR2.34.8 714103Spectre: trans. Simul. crashes with hicum in saturation mode ST5.0.33_USR4* (11/04) 714900Spectre hicum model wrong in DC sweep (fixed by R&D) Atmel5.0.33_ISR(17 or 18) 708954Spectre: self-heating provides a long run time simulation ST5.0.33_USR4* 708569Spectre convergence pb. at low temp. in Hicum ST5.0.33_USR4* (11/04) 708566Spectre: substrate current in hicum bipolar model ST5.0.33_USR4* (11/04)