Lanthanum Oxide for Gate Dielectric Insulator

A feasibility study of La
2
O
3
, one of the rare earth oxides, for replacing SiO
2
gate oxide for CMOS integrated circuits has been reported. It is found that La
2
O
3
after a proper heat treatment has fairly good electrical properties for gate insulator applications in MOSFETs, namely high barrier height for the conduction band electrons and valence band holes as well as its high dielectric constant. The conduction mechanism of La
2
O
3
gate insulator has been modeled, and has been shown to be mainly by space charge limited current (SCLC). Long channel MOSFETs with La
2
0
3
gate insulator has been fabricated, where the best effective mobility is 319 cm
²
/Vs with 2.3 nm of EOT. Interfacial layer (IL) growth suppression due to heat treatment is also reported.