Abstract
We present the materials growth and properties of both epitaxial and amorphous films of Gd 2 O 3 (κ=14) and Y 2 O 3 (κ=18) as the alternative gate dielectrics for Si. The rare earth oxide films were prepared by ultrahigh vacuum vapor deposition from an oxide source. The use of vicinal Si (100) substrates is key to the growth of (110) oriented, single domain films in the Mn 2 O 3 structure. Compared to SiO 2 gate oxide, the crystalline Gd 2 O 3 and Y 2 O 3 oxide films show a reduction of electrical leakage at 1 V by four orders of magnitude over an equivalent oxide thickness range of 10-20 Å. The leakage of amorphous Y 2 O 3 films is about six orders of magnitude better than SiO 2 due to a smooth morphology and abrupt interface with Si. The absence of SiO 2 segregation at the dielectric/Si interface is established from infrared absorption spectroscopy and scanning transmission electron microscopy. The amorphous Gd 2 O 3 and Y 2 O 3 films withstand the high temperature anneals to 850 °C and remain electrically and chemically intact. © 2001 American Institute of Physics.