LEVEL 8 HiCUM Model

What is the HiCUM Model?

HiCUM is an advanced transistor model for bipolar transistors, with a primary emphasis on circuit design for high-speed/high-frequency applications. HiCUM development was spurred by the SPICE Gummel-Poon model's (SGPM) inadequate level of accuracy for high-speed large-signal transient applications and the required high-collector current densities. Other major disadvantages of the SGPM are:

• A lack of sufficient physical background
• Poor descriptions of base resistance and junction capacitances in the regions of interest
• Inadequate description of both Si- and III-V material-based HBTs

The HiCUM model is implemented with LEVEL 8 in Hspice.

HiCUM Model Advantages

Major features of HiCUM are:

• Accurate description of the high-current operating region (including quasi-saturation and saturation).
• Distributed modelling of external base-collector region.
• Proper handling of emitter periphery injection and charge storage .
• Internal base resistance as a function of operating point (conductivity modulation and emitter current crowding), and emitter geometry.
• Sufficiently physical model equations allowing predictions of temperature and process variations, as well as scalability, even at high current densities.
• Parasitic capacitances, independent on operating point, are available in the equivalent circuit, representing base-emitter and base-collector oxide overlaps, that become significant for small-size transistors.
• Weak avalanche breakdown is available.
• Self-heating effects are included. Non-quasi-static effects, resulting in a delay of collector current AND stored minority charge, are modelled as function of bias.
• Collector current spreading is included in minority charge and collector current formulation.
• Extensions for graded-base SiGe HBTs have been derived using the Generalized Integral Charge-Control Relation (GICCR); the GICCR also permits modelling of HBTs with (graded) bandgap differences within the junctions.
• Base-emitter tunneling model is available (e.g., for simulation of varactor leakage).
• Simple parasitic substrate transistor is included in the equivalent circuit.
• Simple parallel RC network taking into account the frequency dependent coupling between buried layer and substrate terminal.
• Parameter extraction is closely related to the process enabling parametric yield simulation; parameter extraction procedure and list of test structures are available; HiCUM parameters can be determined using standard measurement equipment and mostly simple, decoupled extraction procedures.
• Simple equivalent circuit and numerical formulation of model equations result in easy implementation and relatively fast execution time.

These features together with the choice of easily measurable basic variables such as junction capacitances and transit time provide - compared to the SGPM - high accuracy for digital circuit, small-signal high-frequency and, in particular, high-speed large-signal transient simulation. Also, HiCUM is laterally scaleable over a wide range of emitter widths and lengths up to high collector current densities; the scaling algorithm is generic and has been applied to the SGPM (within its validity limits).

In summary, HiCUM's major advantages over other bipolar compact models are:

• Scalability
• Process-based and relatively simple parameter extraction
• Predictive capability in terms of process and layout variations
• Fairly simple numerical formulation facilitating easy implementation and resulting in still reasonable simulation time compared to the (too) simple SGPM at high current densities

Star-Hspice HiCUM Model vs. Public HiCUM Model

Difference Highlights

To maintain flexibility, the Star-Hspice LEVEL 8 HiCUM model uses FBCS, IS, KRBI, MCF, MSR, and ZETACX as additional model parameters. See Other Parameters.

Model Implementation

Model Parameters

Internal Transistors

Transfer Current Parameters

BE Depletion Capacitance Parameters

BC Depletion Capacitance Parameters

Forward Transit Time Parameters

Critical Current Parameters

Inverse Transit Time Parameter

Base Current Components Parameters

Weak BC Avalanche Breakdown Parameters

Internal Base Resistance Parameters

Lateral Scaling

Peripheral Elements

BE Depletion Capacitance

Base Current

BE Tunneling

External Elements

BC Capacitance

BC Base Current Component

Other External Elements

Substrate Transistor Parameters

Collector-Substrate Depletion Capacitance

Substrate Coupling Network

Noise Parameters

Temperature Dependence Parameters

Self-Heating Parameters

Other Parameters

Netlist Input and Output Formats

This section provides the syntax for LEVEL 8 and an example of an input netlist and output format.

Syntax

Qxxx nc nb ne <ns> mname <area> <M=val> <DTEMP=val>

Example

This is an example of a BJT Q1 with collector, base and emitter and substrate connected to nodes 1, 2 and 3 and 4, where the BJT model is given by QM:

Q1 1 2 0 4 QM area=1*0.5*5 dtemp=0.002

Circuit Diagram

Figure 16-15: Large-signal HiCUM/LEVEL2 equivalent circuit

(a) The external BC capacitance consists of a depletion and a bias independent (e.g., oxide) capacitance with the ratio C' BCx / C" BCx being adjusted with respect to proper modelling of the h.f. behavior.

(b) Thermal network used for self-heating calculation.

Input Netlist

.DATA test_data vbe vce vsub 

0.0  0.0  0.0

0.1  0.0  0.0

0.2  0.0  0.0

0.3  0.0  0.0

0.4  0.0  0.0

0.5  0.0  0.0

0.6  0.0  0.0

0.7  0.0  0.0

0.8  0.0  0.0

0.9  0.0  0.0

1.0  0.0  0.0

.ENDDATA

.OPTIONS 

.TEMP 26.85 

VIN 2 0 vbe

VC  1 0 vce

VS  4 0 vsub

VE  3 0 0

Q1 1 2 3 4 hicum 

.DC data= test_data

.PRINT DC I(VIN) i2(q1) I(VC) i1(q1) I(VCS) i4(q1) 

.MODEL hicum NPN  LEVEL=8

+        tref = 26.85

+        c10=.3760000E-31 qp0=.2780000E-13 ich=.2090000E-01

+        hfc=.1000000E+01

+        hfe=1.0000000E+00 hjei=.000000E+00

+        hjci=.100000E+01 tr=1.00000000E-9

+        cjei0=.81100E-14 vdei=.950000E+00 zei=.5000000E+00

+        aljei=.18000E+01

+        cjci0=.11600E-14 vdci=.800000E+00 zci=.3330000E+00

+        vptci=.41600E+03

+        rci0=.127800E+03 vlim=.700000E+00 vpt=.5000000E+01

+        vces=.100000E+00

+        t0=.47500000E-11 dt0h=.210000E-11 tbvl=.400000E-11

+        tef0=.180000E-11 gtfe=.140000E+01 thcs=.300000E-10

+        alhc=.750000E+00

+        fthc=.600000E+00

+        latb=.376500E+01 latl=.342000E+00 fqi=.9055000E+00

+        alit=.450000E+00 alqf=.225000E+00

+        favl=.118600E+01 qavl=.111000E-13 alfav=.82500E-04

+        alqav=.19600E-03

+        ibeis=.11600E-19 mbei=.101500E+01 ibeps=.10000E-29

+        mbep=.200000E+01

+        ireis=.11600E-15 mrei=.200000E+01 ireps=.10000E-29

+        mrep=.200000E+01

+        rbi0=.000000E+00 fdqr0=.00000E+00 fgeo=.730000E+00 

+        fcrbi=.00000E+00

+        cjep0=.00000E+00 vdep=.105000E+01 zep=.4000000E+00 

+        aljep=.24000E+01

+        ceox=.000000E+00

+        cjcx0=.00000E+00 vdcx=.700000E+00 zcx=.3330000E+00 

+        vptcx=.10000E+03

+        ccox=.000000E+00 fbc=.1526000E+00

+        ibcxs=.10000E-29 mbcx=.200000E+01 ibcis=.11600E-19 

+        mbci=.101500E+01

+        cjs0=.000000E+00 vds=.6000000E+00 zs=.44700000E+00 

+        vpts=.100000E+04

+        rcx=.0000000E+00 rbx=.0000000E+00 re=.00000000E+00

+        kf=.00000000E+00 af=.00000000E+00

+        vgb=.1170000E+01 alb=.6300000E-02 alt0=.000000E+00 

+        kt0=.0000000E+00

+        zetaci=.1600E+01 alvs=.100000E-02 alces=.40000E-03

+        zetarbi=0.5880E+00                zetarcx=0.2230E+00

+        zetarbx=0.2060E+00                zetare=0.0000E+00

+        rth=0.0 cth=0.0

+        ibets=.00000E+00 abet=.000000E+00

+        itss=.000000E+00 msf=.0000000E+00 tsf=0.000000E+00 

+        iscs=.000000E+00

+        msc=.0000000E+00

+        rsu=.0000000E+00 csu=.0000000E+00 

.END