High-k Gate-Dielectrics Based on Titanium-Aluminum for Sub-32 Nm CMOS Technology

Abstract

High k insulators for the next generation (sub-32 nm CMOS (complementary metal-oxide-semiconductor) technology), such as titanium-aluminum oxynitride (Ti w Al x O y N z ) and titaniumaluminum oxide (Ti w Al x O y ), have been obtained by Ti/Al e-beam evaporation, with additional electron cyclotron resonance (ECR) plasma oxynitridation and oxidation on Si substrates, respectively. The physical thickness values between 5.7 nm and 6.3 nm were determined by ellipsometry. These films have been used as gate insulators in MOS capacitors, which were fabricated with Al electrodes and final sintering time at 450 0 C for 10 min in forming gas. These capacitors were used to obtain capacitance-voltage (C-V) measurements. A relative dielectric constant of 3.9 was adopted to extract the Equivalent Oxide Thickness of films from C-V curves under strong accumulation condition, resulting in values between 1.9 and 1.7 nm, and the effective charge densities of about 10 11 cm -2 . These results indicate that the obtained