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Turning to electrical data, the most important device electrical data is a plot of threshold voltage versus gate length for the NMOS devices. Figure 7.40 shows typical plots of threshold voltage versus gate length. In this figure, the RTA anneal temperature and times were varied to show the various profiles that can be expected. A more typical plot is represented by the 1000°C RTA profile, showing a peak value around 1-2 microns with a tail off for longer or shorter gate lengths.

Figure 7.40: A plot of Threshold Voltage vs. Gate Length for NMOS devices(given in next module)

Gate oxide thickness measurements are also required. Be careful here if oxide thickness is measured with capacitance-voltage (C-V) methods, since quantum effects in very thin oxides (less than 5nm) can lead to inaccuracies because the actual location of the peak concentration of the accumulation charge is not at the interface as classic physics predicts but a short distance into the silicon. Use the QUANTUM model in ATLAS to match accumulation capacitance with oxide thickness for very thin oxides.

Other useful electrical input information is data that won’t be used now but later for the calibration process itself, testing the predictive nature of the simulation. Typical device characteristics used for predictive testing includes threshold voltage versus gate length measurements for a non-zero substrate bias.

7.8.2: Tuning Oxidation Parameters

During oxidation, interstitials are injected into the silicon substrate by the advancing interface. The first parameter to tune is the fraction of consumed silicon atoms that are re-injected back into the substrate as interstitials. In ATHENA, the related tuning parameter is called THETA.0 and is defined in the INTERSTITIAL statement. THETA.0 has been found to be slightly different for wet and dry oxides. The default value is reasonably accurate for dry oxides but some tuning may be required for wet oxidation.

The major effect of interstitial injection during gate oxidation is to create enhanced diffusion of the threshold adjust implant. The measured threshold voltage of the final device is very sensitive to the dopant concentration near the silicon-gate oxide interface. Consequently, threshold voltage measurements are a sensitive indicator of interstitial behavior. Oxidation, however, is not the only source of interstitial injection. The source-drain and LDD implants also induce a large concentration of interstitials. In order to isolate oxidation enhanced diffusion, the threshold voltage of a long gate length device is used, preferably where L=20 µm or more, so that the threshold voltage will be little influenced by damage near the source-drain regions.

Interstitials injected by source-drain implant damage can travel up to 10 µm along the surface before recombination takes place. A gate length of 20 µm is recommended as the minimum gate length for calibration so this can allow the interstitials to diffuse 10 µm along the surface from both the source and drain ends without effecting diffusion near the center of the device. In summary, tuning THETA.0 involves the comparison of modeled and measured threshold voltage data for a long gate-length device.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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