Theory 09/Semiconductor Physics
Mobility Degrades at a Width Ratio
The claim
Channel mobility degrades when the channel thickness falls below a critical ratio of inversion-layer width, because interface roughness scattering overtakes phonon scattering.
01The mechanism
As the channel narrows, carriers are pushed against the interface; the ratio of channel thickness to wavefunction extent sets how much time they spend being scattered there.
02Predictions
- P1Mobility should drop below a thickness ratio.
- P2Rougher interfaces should shift the threshold.
03Refutation
Mobility independent of the ratio would remove the scattering mechanism.