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Modelling of Silicon Germanium Heterojunction Bipolar
Transistors and its Applications
Staffan Bruce
Licentiate Thesis, Report UPTEC 97126R, November 1997.
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Abstract:
- This thesis concerns modelling of Si/Si1-xGex
Heterojunction Bipolar Transistors (HBT) and its applications.
A physics-based large signal model including thermal
dependence has been developed for Si/Si1-xGex HBTs.
The alloying composition for the modelled device may vary
between 0£ x£0.30, having a pure silicon transistor as a special case.
The model takes into account several effects that are important
for the operation of Si/Si1-xGex HBTs and is directly
related to the parameters in the fabrication process.
Using extraction procedures for only a few parameters that
inherently are difficult to predict, either due to uncertainties
in the fabrication process or due to complex physical relations,
a good agreement is found between the model and measurements.
A new technique for extracting the thermal time constant
of a device using small signal measurements is presented.
The fitting procedure of electrical model parameters
against measured data is described in the DC-case and
particular effects are discussed. In the RF-case, effects
from the variation of key equivalent circuit parameters
on the different scattering parameters are discussed.
With the model, a frequency doubler has been designed and
fabricated. Measured results showed a conversion, from input
frequency of 27.5 GHz to output frequency of 55 GHz, of -14 dB.
Better results can be anticipated since the HBT in the fabricated
circuit differed from the one used in the design. The agreement
between simulated and measured data were good.
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Keywords:
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SiGe, HBT, Large-signal modelling, thermal time constant,
frequency doubler.
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Related publications:
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Extraction of thermal time constant in HBTs using small signal measurements.Electronics Letters 1997.
In Postscript :
compressed(gz) 64K
, uncompressed 334K.
- On the design of a 55 GHz Si/SiGe HBT frequency doubler
operating close to fmax.
Proc. 26th European Microwave Conference, Prague 1996.
In Postscript :
compressed(gz)584K ,
uncompressed1.56M.
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Development, implementation and verification of a physics-based
Si/SiGe HBT model for millimeter-wave non-linear circuit simulations.
Proc. 26th European Microwave Conference, Prague 1996.
In Postscript :
compressed(gz)30K ,
uncompressed131K.
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Source:
- Introduction
in Postscript, 58K ;
in Pdf, 18K
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