Band edge high-K /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-K/Metal nMOSFETs with good mobility (190 cm 2/Vs @ 1MV/cm) at Tinv (1.45 nm), in a gate first process flow. It is shown that Vt 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. © 2007 IEEE.