Band Edge High-κ/Metal Gate n-MOSFETs Using Ultra Thin Capping Layers

Ultra thin layers of Magnesium containing cap layers are deposited on Hf based dielectrics prior to deposition of the TiN/Poly-Si electrode stack [1] to achieve
Band-edge (BE) high-κ/metal nMOSFETs
with good mobility (190 cm
²
/Vs @ 1 MV/cm) at T
_inv
(1.45 nm), in a gate first process flow. It is shown that V
_t
can be modulated anywhere between midgap and band edge by changing the cap layer thickness. Short channel devices with band edge characteristics are demonstrated down to 40 nm.