Junction Capacitor (juncap_eldo)
The juncap model is intended to describe the behavior of the juncaps that are formed by the source, drain or well-to-bulk junctions in MOS devices. It is described in the Phillips MOST Modelbook (Dec.93) as JUNCAP model. Information on how to obtain this document can be found on Source Link by searching for Phillips (c) Phillips Electronics N.V. 1994
In extension to the model book description a minimum conductance gmin is inserted between the juncap nodes, to aid convergence. The value of gmin is set by an options statement, default = 1e-12 S.
The imax parameter is used to aid convergence and to prevent numerical overflow. The junction characteristics of the junction capacitor are accurately modeled for currents up to imax. For currents above imax, the junction is modeled as a linear resistor and a warning is printed.
This device is supported within altergroups.
This device is dynamically loaded from the shared object /vols/mmsimP4_t1b_006/ws/ling/ling_2110_isr3_mif/spectre_dev/tools.lnx86/cmi/lib/64bit/5.0.doc/libphilips_sh.so.
Sample Instance Statement
c2 (1 2) capmod ab=7e-12 lg=5e-6 region=rev
Sample Model Statement
model capmod juncap type=n cjbr=0.2 cjgr=0.2 cjsr=0.2 tref=25 jsgbr=2e-3 jsdbr=0.28e-3 jsggr=1e-5 jsdgr=0.33e-6 vdsr=0.8 vdgr=0.8 vdbr=0.8
Instance Syntax
Name n [b] ModelName parameter=value ...
Instance Parameters
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ab=1.0 scale2 m2
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Diffusion area. Scale set by option scale.
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ls=1.0 scale m
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Length of the sidewall of the diffusion area ab which is not under the gate. Scale set by option scale.
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lg=1.0 scale m
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Length of the sidewall of the diffusion area ab which is under the gate. Scale set by option scale.
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m=1.0
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Multiplicity factor.
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region=rev
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Estimated DC operating region, used as a convergence aid. Possible values are fwd or rev.
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Model Syntax
model modelName juncap_eldo parameter=value ...
Model Parameters
Structural parameters
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type=n
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Type of the juncap device. Possible values are n or p.
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vb (V)
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Not used for juncap model.
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bv (V)
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Alias of vb.
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level
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Not used for juncap model.
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Current parameters
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jsgbr=1.0e-3 A/m2
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Bottom saturation-current density due to electron-hole generation at reference voltage.
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jsdbr=1.0e-3 A/m2
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Bottom saturation-current density due to diffusion from back contact.
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jsgsr=1.0e-3 A/m
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Sidewall saturation-current density due to electron-hole generation at reference voltage.
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jsdsr=1.0e-3 A/m
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Sidewall saturation-current density due to diffusion from back contact.
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jsggr=1.0e-3 A/m
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Gate edge saturation-current density due to electron-hole generation at reference voltage.
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jsdgr=1.0e-3 A/m
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Gate edge saturation-current density due to diffusion from back contact.
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imax=1.0 A
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Explosion current.
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Temperature effects parameters
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dta=0.0 K
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Temperature offset of the juncap element with respect to ambient temperature.
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trise=0.0 K
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Alias of dta.
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tr (C)
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Temperature at which the parameters have been determined. Default set by option tnom.
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tref (C)
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Alias of tr. Default set by option tnom.
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tnom (C)
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Alias of tr. Default set by option tnom.
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Junction capacitance parameters
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cjbr=1.0e-12 F/m2
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Bottom junction capacitance at reference voltage.
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cjsr=1.0e-12 F/m
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Sidewall junction capacitance at reference voltage.
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cjgr=1.0e-12 F/m
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Gate edge junction capacitance at reference voltage.
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Emission coefficient parameters
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nb=1.0
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Emission coefficient of the bottom forward current.
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ns=1.0
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Emission coefficient of the sidewall forward current.
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ng=1.0
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Emission coefficient of the gate-edge forward current.
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Voltage parameters
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vr=0.0 V
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Voltage at which parameters have been determined.
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vdbr=1.0 V
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Diffusion voltage of the bottom junction at reference temperature.
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vdsr=1.0 V
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Diffusion voltage of the sidewall junction at reference temperature.
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vdgr=1.0 V
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Diffusion voltage of the gate edge junction at reference temperature.
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Grading coefficient parameters
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pb=0.4
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Bottom-junction grading coefficient.
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ps=0.4
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Sidewall-junction grading coefficient.
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pg=0.4
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Gate edge-junction grading coefficient.
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Compatibility model parameters
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compatible=spectre
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Encourage device equations to be compatible with a foreign simulator. This option does not affect input syntax. Possible values are spectre, spice2, spice3, cdsspice, or spiceplus.
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Output Parameters
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cjb (F)
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Capacitance of bottom area ab.
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cjs (F)
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Capacitance of locos-edge ls.
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cjg (F)
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Capacitance of gate-edge lg.
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isdb (A)
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Diffusion saturation-current of bottom area ab.
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isds (A)
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Diffusion saturation-current of locos-edge ls.
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isdg (A)
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Diffusion saturation-current of gate-edge lg.
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isgb (A)
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Generation saturation-current of bottom area ab.
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isgs (A)
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Generation saturation-current of locos-edge ls.
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isgg (A)
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Generation saturation-current of gate-edge lg.
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vdb (V)
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Diffusion voltage of bottom area ab.
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vds (V)
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Diffusion voltage of locos-edge ls.
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vdg (V)
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Diffusion voltage of gate-edge lg.
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Operating-Point Parameters
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v (V)
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juncap bias voltage ( v = va - vk ).
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i (A)
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Total resistive current from anode to cathode ( i = ia = -ik ).
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gm (S)
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Total differential conductance.
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q (Coul)
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Total junction charge ( q = qa = -qk ).
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c (F)
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Total capacitance.
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pwr (W)
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Power.
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Related Topics
Fractional Impedance/Admittance Pole (fracpole)
Two-Terminal Capacitor (capacitor)
Two Terminal Capacitor with the specified Q factor (capq)
JUNCAP2 Model (juncap200)
Junction Capacitor (juncap)
Passive Components
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