AVS 52nd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP36
Characteristics of Lanthanum Oxide Prepared using La(iPrCp)@sub 3@ and H@sub 3@O

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Electronic Materials and Processing Poster Session
Presenter: S.Y. No, Seoul National University, Korea
Authors: S.Y. No, Seoul National University, Korea
D. Eom, Seoul National University, Korea
C.S. Hwang, Seoul National University, Korea
H.J. Kim, Seoul National University, Korea
Correspondent: Click to Email
According to scaling rule, high @kappa@ gate dielectric stack with equivalent oxide thickness (EOT) below 1 nm will be required for sub-0.1µm devices. La-based oxides are attractive candidates for this purpose because of high-@kappa@ value, good interfacial properties, and large band offset against the Si. In this report, we deposited lanthanum oxide thin films using La(iPrCp)@sub 3@ (Tris(isopropylcyclopentadienyl)Lanthanum) and H@sub 2@O. The La precursor and H@sub 2@O were injected alternately and purged by Ar gas between the injections. The deposited films underwent various rapid thermal annealing (RTA), and the property changes were investigated. The deposited films contained carbon impurity less than 1 at.% and showed smooth surface (root mean square roughness< 0.1 nm, ~5 nm film). The electrical properties of deposited films were measured on Pt/Lanthanum oxide/p-Si(100) structure, and small frequency dispersion and hysteresis (<10 mV) were observed in capacitance vs. voltage measurement. The film structures were observed by high-resolution transmission electron microcopy, and the chemical states of interfacial and upper layer were analyzed by angle-resolved X-ray photoelectron spectroscopy. The film showed amorphous structure even after RTA at 900°C. However, chemical states were altered significantly with a change of valence band offset by the RTA. With optimized RTA condition, capacitance equivalent oxide thickness (CET) below 1.1nm was obtained with fairly reduced positive fixed charge density, and accompanied interfacial reaction lead to a decrease of interface trap density.