We have examined an origin of the flatband voltage (VFB) shift in metal-oxide-semiconductor capacitors by employing bilayer high-k gate dielectrics consisting of HfO2 and Al2O3 on the interfacial SiO2 layer. We found that the high-k∕SiO2 interface affects the VFB shift through an electrical dipole layer formation at its interface, regardless of the gate electrode materials. Furthermore, we demonstrated that the VFB shift in the metal/high-k gate stack is determined only by the dipole at high-k∕SiO2 interface, while for the Si-based gate it is determined by both gate/high-k and high-k∕SiO2 interfaces.

The effects of the nitrogen in the HfSiON gate dielectric on the electrical and thermal properties of the dielectric were investigated. It is clearly demonstrated that nitrogen enhances the dielectric constant of silicates. High dielectric constants of the HfSiON are maintained and boron penetration is substantially suppressed in the HfSiON during high temperature annealing. These properties are ascribed to the homogeneity of the bond structure in the film containing nitrogen through high temperature annealing.

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To realize a stackable complementary metal–oxide–semiconductor field-effect transistor (CMOSFET) on interlayer dielectrics for three-dimensional (3D) large-scale-integration devices, we investigated poly-Ge thin films formed by flash lamp annealing. The process resulted in crystalline grains of micrometer-order size, and the Hall-effect mobility of holes was as high as 200 cm2 V−1 s−1. A depletion-type trigate poly-Ge channel pMOSFET with a gate length of 80 nm formed on a poly-Ge film exhibited a drive current of 280 µA/µm at a drain voltage of −1 V and a gate overdrive of −1 V. The operation of inversion-type short-channel trigate poly-Ge nMOSFETs was also demonstrated.