ZINC

Set the coefficients of zinc kinetics.

SYNOPSIS

zinc
( silicon | oxide | oxynit | nitride | gas | poly | gaas )
[ Dix.0 = n ] [ Dix.E = n ] [ Dip.0 = n ] [ Dip.E = n ]
[ Dipp.0 = n ] [ Dipp.E = n ] [ Fi = n ]
[ implanted ] [ grown.in ]
[ ss.clear ] [ ss.temp = n ] [ ss.conc = n ]
[ ( /silicon | /oxide | /oxynitr | /nitride | /gas | /poly | /gaas ) ]
[ Seg.0 = n ] [ Seg.E = n ] [ Trn.0 = n ] [ Trn.E = n ]
[ ( donor | acceptor ) ]

DESCRIPTION

This statement allows the user to specify values for coefficients of zinc diffusion and segregation. The diffusion equation for zinc is:

where CT and CA are the total chemical and active concentrations of zinc, CA is the total electrically active concentration of zinc, CV and CI are the vacancy and interstitial concentrations, the superscript * refers to the equilibrium value, DV and DI are the diffusivities with vacancies and interstitials, and p and ni refer to the hole concentration and the intrinsic electron concentration respectively. The diffusivities are given by:

DX, DP, and DPP are described in greater detail below.

The segregation at material interfaces is computed using the following expression:

where C1 and C2 are the concentrations in material 1 and 2 respectively, and the M12 and Tr terms are computed using expressions shown below with the parameters of the models.

silicon, oxide, oxynitr, nitride, gas, poly, gaas
These allow the specification of parameters for that material. Only one of these can be specified per statement. The parameters specified in that statement will apply in the material listed. These parameters specify which material is material 1 for the segregation terms.

Dix.0, Dix.E
These floating point parameters allow the specification of DX, the zinc diffusivity with neutral defects. Dix.0 is the pre-exponential constant and Dix.E is the activation energy. Dix.0 defaults to 0.0 cm2/sec in gallium arsenide, and Dix.E defaults to 0.0 eV in gallium arsenide. DX is calculated using a standard Arrhenius relationship.

Dip.0, Dip.E
These floating point parameters allow the specification of DP, the zinc diffusivity with singly positive defects. Dip.0 is the pre-exponential constant and Dip.E is the activation energy. Dip.0 defaults to 0.0 cm2/sec in gallium arsenide, and Dip.E defaults to 0.0 eV in gallium arsenide. DP is calculated using a standard Arrhenius relationship.

Dipp.0, Dipp.E
These floating point parameters allow the specification of DPP, the zinc diffusivity with doubly positive defects. Dipp.0 is the pre-exponential constant and Dipp.E is the activation energy. Dipp.0 defaults to 1.2E2 cm2/sec for implanted zinc in gallium arsenide and 15.6 cm2/sec for grown-in zinc in gallium arsenide, and Dipp.E defaults to 3.9 eV for both in gallium arsenide[1,2]. DPP is calculated using a standard Arrhenius relationship.

Fi
This parameter allows the specification of the fractional interstitialcy. This value indicates whether zinc diffuses through interaction with interstitials or vacancies. The value of Fi defaults to 1.0.

implanted, grown.in
Specifies whether the Dix, Dip, Dipp, or Fi coefficients apply to implanted or grown-in zinc. If neither is specified then a specified parameter applies to both.

ss.clear
This parameter clears the currently stored solid solubility data.

ss.temp, ss.conc
These parameters add a single temperature solid solubility concentration point to those already stored. The default values are:

/silicon, /oxide, /oxynit, /nitride, /gas, /poly, /gaas
These parameters specify material 2. Only one of the these parameters can be specified at one time.

Seg.0, Seg.E
These parameters allow the computation of the equilibrium segregation concentrations. The segregation constant follows an Arrhenius relationship.

Trn.0, Trn.E
These parameters allow the specification of the transport velocity across the interface given. The units are in cm/sec. The transfer coefficient follows an Arrhenius relationship.

donor, acceptor
These parameters determine whether the impurity is to be treated as a donor or as an acceptor in a semiconductor material. These parameters are not presently material specific. By default, zinc is an acceptor.

EXAMPLES

zinc gaas implanted Dip.0=2.2e-6 Dip.E=1.76
This command changes the positive defect diffusivity for implanted zinc in gallium arsenide.

zinc gaas /nitride Seg.0=1126.0 Seg.E=0.91 Trn.0=1.66e-7
This command will change the segregation parameters at the gallium arsenide - silicon nitride interface. The gallium arsenide concentration will be half the nitride concentration in equilibrium at 1100C.

BUGS

As far as the implemented models are physically correct, there are no known bugs.

REFERENCES

  1. J. D. Plummer et al., "Process Simulators for Si VLSI and High Speed GaAs Devices," Stanford University Technical Report, 1990.
  2. J. D. Plummer et al., "Process Simulators for Si VLSI and High Speed GaAs Devices," Stanford University Technical Report, 1991.

SEE ALSO

The antimony, arsenic, beryllium, boron, carbon, generic, germanium, interstitial, magnesium, phosphorus, selenium, isilicon, tin, and vacancy statements.