201
Noise in Strain-Engineered Devices
illustrated for strained MOSFETs as well as multigate FETs and nanowires.
The mean capture and emission times are extracted from RTS, and their
bias dependency has been demonstrated. The study of bias dependency has
been demonstrated for extraction of trap locations responsible for the noise
fluctuations. Low-frequency noise study in SiGe:C heterojunction bipolar
transistors is also included, for which the mechanism is little different from
the MOSFETs. Flicker noise characteristics and their corresponding power
spectral densities have been observed, and their bias dependencies are demonstrated. The origins of random telegraph noise are depicted by recombination centres and electrically active defect states formed by carbon atoms via
a generation–recombination mechanism in the base of the SiGe:C HBT. The
amplitude scaling of the RTS is observed either with the total base current or
with a nonideal base current component. The two-capture process and tunneling of a carrier from the neutral region are described as the fundamental
noise-generating mechanisms in the bipolar transistors.
Review Questions
1. What are the fundamental noise sources in a semiconductor?
2. 1/f noise affects the performance of RF circuits. (True/False)
3. Noise measurements may be used as a diagnostic tool for defect
determination. (True/False)
4. Addition of carbon affects the noise performance of SiGe:C HBTs.
(True/False)
5. Electrically active defect states formed by carbon atoms via a
generation–recombination mechanism are responsible for 1/f noise
in SiGe:C HBTs. (True/False)
6. Thermal noise originates from the random thermal movement of
electrons. (True/False)
7. The origin of 1/f noise in MOS transistors is due to carrier number
fluctuation noise due to traps in the gate oxide. (True/False)
8. Shot noise is generated when the electrons cross the barrier independently and randomly. (True/False)
9. Generation–recombination noise in semiconductors originates
from random capture or emission of carriers by localised charge
centres. (True/False)
10. A mobility fluctuation noise model is used to explain the 1/f
noise. (True/False)
Noise in Strain-Engineered Devices
illustrated for strained MOSFETs as well as multigate FETs and nanowires.
The mean capture and emission times are extracted from RTS, and their
bias dependency has been demonstrated. The study of bias dependency has
been demonstrated for extraction of trap locations responsible for the noise
fluctuations. Low-frequency noise study in SiGe:C heterojunction bipolar
transistors is also included, for which the mechanism is little different from
the MOSFETs. Flicker noise characteristics and their corresponding power
spectral densities have been observed, and their bias dependencies are demonstrated. The origins of random telegraph noise are depicted by recombination centres and electrically active defect states formed by carbon atoms via
a generation–recombination mechanism in the base of the SiGe:C HBT. The
amplitude scaling of the RTS is observed either with the total base current or
with a nonideal base current component. The two-capture process and tunneling of a carrier from the neutral region are described as the fundamental
noise-generating mechanisms in the bipolar transistors.
Review Questions
1. What are the fundamental noise sources in a semiconductor?
2. 1/f noise affects the performance of RF circuits. (True/False)
3. Noise measurements may be used as a diagnostic tool for defect
determination. (True/False)
4. Addition of carbon affects the noise performance of SiGe:C HBTs.
(True/False)
5. Electrically active defect states formed by carbon atoms via a
generation–recombination mechanism are responsible for 1/f noise
in SiGe:C HBTs. (True/False)
6. Thermal noise originates from the random thermal movement of
electrons. (True/False)
7. The origin of 1/f noise in MOS transistors is due to carrier number
fluctuation noise due to traps in the gate oxide. (True/False)
8. Shot noise is generated when the electrons cross the barrier independently and randomly. (True/False)
9. Generation–recombination noise in semiconductors originates
from random capture or emission of carriers by localised charge
centres. (True/False)
10. A mobility fluctuation noise model is used to explain the 1/f
noise. (True/False)