Gd silicate: A high- k dielectric compatible with high temperature annealing

The authors report on the investigation of amorphous Gd-based silicates as high- k dielectrics. Two different stacks of amorphous gadolinium oxide ( Gd 2 O 3 ) and silicon oxide ( Si O 2 ) on silicon substrates are compared after annealing at temperatures up to 1000 ° C . Subsequently formed metal oxide semiconductor capacitors show a significant reduction in the capacitance equivalent thicknesses after annealing. Transmission electron microscopy, medium energy ion scattering, and x-ray diffraction analysis reveal distinct structural changes such as consumption of the Si O 2 layer and formation of amorphous Gd silicate. The controlled formation of Gd silicates in this work indicates a route toward high- k dielectrics compatible with conventional, gate first complementary metal-oxide semiconductor integration schemes.