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Noise combined with S-Pisces or Blaze allows analysis of the
small-signal noise generated within semiconductor devices. Noise
provides accurate characterization of all small-signal noise sources
and extracts figures of merit which are essential for optimizating
circuit design.
Advanced Semiconductor Noise Analysis
- Noise simulations may be performed on any one or two-port
device and supports all material systems within the ATLAS
framework
- Noise sources modeled include; diffusion noise,
generation-recombination noise, and flicker (1/f) noise for both
electrons and holes
- Direct extraction of standard industry figures of merit such
as minimum noise figure Fmin, optimum source impedence Z0, and
noise conductance gn
- Additional outputs include individual microscopic noise
sources (MNS), the total local noise source (LNS), the impedence
field and short-circuit Green’s function
- Noise voltage correlation spectra due to local microscopic
noise sources are modeled using a fast and efficient
implementation of the direct impedence field method
- Noise may be applied to either the drift-diffusion equations
or the more sophisticated hydrodynamic transport models
- Noise provides ease of use with no user calibration required
for diffusion noise or GR noise
- Seamless interface to the Silvaco C-Interpreter module allows
users to implement new and unique noise source equations
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A 0.5um deep trench isolated double poly
SiGe HBT with an emitter area of 40um2 simulated using the 2D
process simulator ATHENA.
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Minimum noise figure verses collector
current for the poly SiGe HBT at three frequencies of interest
for wireless applications-2, 5 and 10 GHz.
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Noise Analysis of two-port Devices
Noise provides the ability to investigate and optimize the noise
behavior at any operating bias point. Of prime concern to RF
engineers is the trade off between achieving a low noise figure, a
high operating current and a sufficiently high current gain.
SiGe HBT Example
A trench isolated double poly SiGe HBT was simulated using the
process simulator ATHENA and then was parsed to ATLAS for noise
analysis at various bias points.
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Gain verses collector current for the poly
SiGe HBT at three frequencies of interest for wireless
applications-2, 5 and 10 GHz.
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The two-dimensional contours of the electron
microscopic diffusion noise source (MNS) is shown in this
figure. The MNS is the amount of noise generated by the volume
of the device surrounding a node. |
90nm MOSFET Example
A 90nm silicon MOSFET was simulated using the 2D process
simulator ATHENA to provide an accurate description of the physical
structure. The structure is then seamlessly parsed to the device
simulator ATLAS for noise analysis for various operating points.
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The two-dimensional contours of the electron
local diffusion noise source (LNS) is shown in this figure.
The LNS is the amount of noise generated on a contact by the
volume of the device surrounding a node. This is calculated by
translating the MNS into a contact voltage using the impedance
field. |
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This figure shows the variation of the noise
conductance with frequency. The noise conductance is a measure
of how the noise figure increases as the source impedance
moves away from the optimum source impedance.
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This figure shows the two-port noise figure
Fmin as the frequency is varied from 1kHz to 10GHz.
The noise figure is a measure of the extra noise that the
device adds to the signal reaching the load. It is defined as
the noise power delivered to the load, but the noisy source
and the noisy device, divided by the noise power that would be
delivered to the load if the source were noisy but the device
was ideal.
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Rev.
012304_01 |