IMPLANT

Perform ion implantation.

SYNOPSIS

implant
( antimony | arsenic | boron | bf2 | cesium | phosphorus | beryllium | magnesium | selenium | isilicon | tin | germanium | zinc | carbon | generic )
[ gauss | pearson ] dose = n energy = n
[ damage ] [ max.damage = n ]
[ range = n ] [ std.dev = n ] [ gamma = n ] [ kurtosis = n ] [ angle = n ]

DESCRIPTION

This statement is used to simulate ion implantation. There are two different types of analytic models available. The first implements a simple Gaussian distribution. The second uses the moments data file to compute a Pearson-IV distribution. These models are only as good as the data in the files. The file data can be overridden by directly specifying the appropriate values on the implant command line.

antimony, arsenic, boron, bf2, cesium, phosphorus, beryllium | magnesium | selenium | isilicon | tin | germanium | zinc | carbon
These parameters specify the impurity to be implanted. Default data for the range statistics exists only for antimony, arsenic, boron, BF2, phosphorus, beryllium, magnesium, selenium, isilicon, tin, germanium, zinc, and carbon.

gauss, pearson
These parameters specify which type of distribution is being used. A Pearson-IV distribution is the default.

dose
This parameter allows the user to specify the dose of the implant. The units are in atoms/cm2.

energy
This parameter specifies the implant energy in KeV.

damage
This parameter indicates that a computation of the damage due to the implant should be performed. The data is from Hobler and Selberherr [1] and exists only for antimony, arsenic, boron, and phosphorus.

max.damage
The maximum amount of damage to the crystal that makes sense to calculate. Clearly damage above the crystal density is absurd.

range, std.dev, gamma, kurtosis
These parameters allow the user to override the table values. The full set of data has to be given. It is not possible, for instance, to override only the range parameter. The gamma and kurtosis variables only have meaning for the Pearson-IV distribution.

angle
This parameter allows the user to specify the angle normal to the substrate that the impurity was implanted at.

EXAMPLES

implant phosph dose=1e14 energy=100 pearson
This statement specifies that a 100 KeV implant of phosphorus was done with a dose of 1.E14 cm-2. The Pearson-IV model is to be used for the distribution function.

implant phos dose=1e14 range=0.1 std.dev=0.02 gauss
This statement specifies an implant of phosphorus was done with a dose of 1.E14 cm-2. The Gaussian model is to be used for the distribution function. The range and standard deviation are specified in microns instead of using table values.

implant phosph dose=1e14 energy=100 pearson damage
This statement specifies that a 100 KeV implant of phosphorus was done with a dose of 1.E14 cm-2. The Pearson-IV model is to be used for the distribution function. The damage from this implant is calculated and stored as point defects.

BUGS

Very high angle implants may have non-physical profiles near the device edges.

Occasionally problems are encountered on undercut surfaces and other reentrant shapes. The algorithm really wasn't intended for these types of shapes.

REFERENCES

  1. G. Hobler and S. Selberherr, "Two-Dimensional Modeling of Ion Implantation Induced Point Defects," IEEE Trans. on CAD, 7(2), p. 174, 1988.