Source-gated%20Transistor

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Source-gated Transistor
Seokmin Hong
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Why do we need it?
Short Channel Effects Source/Drain Charge
Sharing Drain-Induced Barrier Lowering
Subsurface Punchthrough Mobility
Degradation Velocity Saturation And so on
No details, no explanation, only a kneeling of
Intel's CEO and an excuse We are in the
transition towards a new architecture
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Metal-Semiconductor Contact
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Rectifying Contacts
Forward bias
Reverse bias
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Some terminologies
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Conventional Metal source and drain structure
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Conduction band minimum
Vg1V, Vd0.2V
Vg0V, Vd0.2V
Vg1V, Vd0V
C.-K. Huang, W.E. Zhang, and C.H. Yang,
Two-dimensional numerical simulation of Schottky
barrier MOSFET with channel length to 10nm,
IEEE Trans. Electron Devices, vol. 45,
pp842-848.1998.
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Performance ??
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Source-gated structure

• Small Saturation Voltage
• (Saturation voltage coincides with
• Vt(threthold voltage))
• High Output Resistance

d L2um,Same semiconductor insulation
deposition
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Transport Mechanism
We constrict the flow of carriers using a source
barrier and use the field effect to change the
effective height of the barrier and the magnitude
of the current. As the drain voltage is
increased, the whole semiconductor region between
the source and gate becomes depleted of charge.
When this happens, the source current is
determined by the voltage on the gate and is
insensitive to further increase of voltage on the
drain.
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Basic Strategy
Metal (Source)
Metal (Gate)
Oxide
Semiconductor
1-D MOSFET
Extraction of Band Bending
Then we can get current using NEGF.
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I-V relation between source and drain-(1)
Relatively large leakage current when the
transistor Is off.
Barrier Height 0.2 V Channel 3 nm Oxide
thickness 1 nm Vg0/0.25/0.5/0.75/1 V
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I-V relation between source and drain-(1)
Barrier Height 0.3 V Channel 3 nm Oxide
thickness 1 nm Vg0/0.25/0.5/0.75/1 V
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I-V relation between source and drain-(1)
Reduced off-current
Barrier Height 0.3 V Channel 6 nm Oxide
thickness 2 nm Vg0/0.5/1/1.5/2 V
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Source-gated transistor is fundamentally 2-D
structureso it needs 2-D simulation!
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