Mos Metaloxidesemiconductor Physics And Technology Ehnicollian | Jrbrewspdf Hot

The subthreshold swing (SS) is the gate voltage needed to change drain current by one decade:

[ SS = \frackTq \ln(10) \left( 1 + \fracC_depC_ox \right) \approx 60 \text mV/dec at 300K (ideal) ] The subthreshold swing (SS) is the gate voltage

Any SS > 60 mV/dec wastes power. Steep-slope devices (TFETs, negative capacitance FETs) aim to beat this limit. | Layer | Traditional Material | Modern/Advanced Material

| Layer | Traditional Material | Modern/Advanced Material | |----------------|----------------------|-------------------------------------| | Metal (Gate) | Aluminum, Poly-Si | TiN, TaN, W, Mo (metal gates) | | Oxide | SiO₂ (~1–10 nm) | High-κ dielectrics (HfO₂, ZrO₂, Al₂O₃) | | Semiconductor | Si (p- or n-type) | Si, SiGe, GaN, SiC (for power/RF) | Poly-Si | TiN

At the heart of MOS physics is band bending. In thermal equilibrium, the Fermi level is constant. Applying a gate voltage bends the conduction and valence bands at the surface. The surface potential ( \psi_s ) (in volts) quantifies this bending. Strong inversion occurs when ( \psi_s = 2\phi_F ).