MOSFET SCALING

High K Metal Gate Technology (HKMG)

Dielectric leakage problem

•Dielectric leakage is problem faced during scaling the MOSFET

•This happens because of the tunneling of the electrons through the thin dielectric

•As the width(physical) of the dielectric reduces leakage becomes more due to tunneling

High K Solution

• The problem however can be overcome by the usage of High K dielectric.This shows that the ,material must be electrically thin but physically thick(Hafnium oxide ).For the same capacitance the oxide thickness of the high K dielectric (oxide) can be more .

Problem with the polysilicon gate

• Polysilicon depletion
• Need for enhanced channel mobility

Potential solution

•No depletion, very low resistance gate, no boron penetration, compatibility with high-k

•Also lesser phonon scattering, hence enhanced mobility