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The choice of model or combination of models for any of the process steps described above is defined in the METHOD statement. The METHOD statement serves a number of functions but in the context of defining damage models the METHOD statement is used for two purposes.

The first purpose is to specify models for how damage is induced during processes such as implantation or oxidation. The second purpose is to specify how that damage anneals and diffuses in subsequent or concurrent thermal processes.

It’s important to realize that the METHOD statement must be placed above the line, specifying the process step or steps to which it refers in the input file. Any number of method statements can be used in an input file allowing you to change the models at will during the process flow to optimize the speed and accuracy of the simulation. The models specified in the METHOD statement will hold true for all processes that follow it until it’s updated by a subsequent method statement.

Table 7.5 below indicates a recommended method statement for typical processes. It should be realized that these statements are hierarchical, so there is no accuracy lost if a more complicated model is used where a simpler one would suffice. The only downside here is a longer simulation time. The table below starts off with the simplest of models and progresses to the more complicated ones.

Table 7.5. Recommended Method Statements for Typical Processes.

Method Statement Syntax Suitability of using this method
method fermi Use only before undamaged silicon diffusions, where doping concentrations are less than 1e20/cm3 and no oxidizing ambient is present.
method two.dim Use before implant doses less than 1e13/cm2 and for oxidations.
method full.cpl cluster.dam high.conc Use before implant doses greater than 1e13/cm2

7.7.3.3. : Changing the Method Statement During the Process Flow

It has previously been stated that the disadvantage of using the most advanced and complex models is the time involved during diffusion cycle simulation. Accordingly, there is an incentive during complex process simulations to switch back to a simpler model during a diffusion cycle when the majority of the damage created by a previous implant has been annealed. We will show you when to switch to a simpler model.

If the process being modeled has involved implantation or oxidation at any stage, we advise not to use the fermi model. An exception to this would be in some power devices with very long diffusion times where the exact nature of surface damage would have little impact on the final distribution of the dopant and simulation time is at a premium.

In reality, for most small geometry processes, the question of switching models becomes one of when to add a new method statement that changes from:

METHOD FULL.CPL CLUSTER.DAM HIGH.CONC

to

METHOD TWO.DIM

after a high dose implant.

7.7.3.4. Switching Guidelines.

A simple guideline to follow when to switch method statements during a process flow is by switching back to the TWO.DIM model if the anneal temperature is greater than 900° and the device has been annealed for at least one minute, following an implant where the dose is greater than 1e13/cm^2.

Questions & Answers

what does nano mean?
Anassong Reply
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Bharti
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s. Reply
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are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
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SUYASH Reply
for screen printed electrodes ?
SUYASH
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s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
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Cied
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what's the easiest and fastest way to the synthesize AgNP?
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Cied
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Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
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