A Physical Understanding of RF Noise in Bulk nMOSFETs With Channel Lengths in the Nanometer Regime

A Physical Understanding of RF Noise in Bulk nMOSFETs With Channel Lengths in the Nanometer Regime

Experimental and simulation results of high-frequency channel noise in MOSFETs with 40-, 80-, and 110- nm gate lengths are presented. The measured dc I - V characteristics can be matched using the drift-diffusion (DD) and hydrodynamic (HD) transport models, both incorporating velocity saturation. Th...

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Bibliographic Details
Published in:IEEE transactions on electron devices Vol. 59; no. 1; pp. 197 - 205
Main Authors: Mahajan, V. M., Patalay, P. R., Jindal, R. P., Shichijo, H., Martin, S., Hou, F., Machala, C., Trombley, D. E.
Format: Journal Article
Language:English
Published: New York, NY IEEE 01-01-2012
Institute of Electrical and Electronics Engineers
Subjects:
Applied sciences
Carrier heating
carrier transport
channel-length modulation (CLM)
device simulation
diffusion noise
drift-diffusion (DD)
Electronics
Exact sciences and technology
excess channel noise
Heating
High definition video
hydrodynamic (HD)
impedance-field method
Logic gates
MOSFETs
Noise
Radio frequency
RF noise
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Semiconductor process modeling
shot noise
Transistors
velocity saturation
MOSFET
Voltage current curve
Circuit design
carrier transport
device simulation
Relaxation time
Energy relaxation
Transport process
excess channel noise
diffusion noise
Direct current
Carrier heating
Impact ionization
Computer aided design
Drift mobility
Electrical characteristic
RF noise
MOS technology
impedance-field method
channel-length modulation (CLM)
velocity saturation
drift-diffusion (DD)
Hydrodynamic model
Shot noise
High frequency
Impedance
NMOS technology
Simulator
hydrodynamic (HD)
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Description
Summary:Experimental and simulation results of high-frequency channel noise in MOSFETs with 40-, 80-, and 110- nm gate lengths are presented. The measured dc I - V characteristics can be matched using the drift-diffusion (DD) and hydrodynamic (HD) transport models, both incorporating velocity saturation. The DD model grossly underestimates the measured noise, demonstrating the inadequacy of channel-length modulation and impact ionization to explain the excess noise. The HD model generates higher noise but not enough, showing that introduction of carrier heating is still insufficient to explain the experimental results. The underprediction of noise using the HD model can be mitigated by a suitable choice of the energy relaxation time and saturation velocity; however, simultaneous matching of both noise and dc I - V does not produce satisfactory results. Thus, TCAD simulators are unable to simulate this excess-noise mechanism at this time. Experimental data support that, at 40 nm gate lengths, noise can be described by a shot noise like expression.
ISSN:0018-9383
1557-9646
DOI:10.1109/TED.2011.2173691