AVS 49th International Symposium
    Dielectrics Thursday Sessions
       Session DI+EL-ThM

Paper DI+EL-ThM6
Plasma Enhanced MOCVD of Hafnium Oxide and Hafnium Silicate Thin Films

Thursday, November 7, 2002, 10:00 am, Room C-107

Session: Issues for Gate Dielectrics
Presenter: H. Bhandari, University of Alabama
Authors: V. Rangarajan, University of Alabama
H. Bhandari, University of Alabama
T.M. Klein, University of Alabama
Correspondent: Click to Email
Hafnium oxide films were deposited by Metal Organic Chemical Vapor Deposition (MOCVD) on Si using hafnium t-butoxide as the metal organic precursor. X-ray diffraction data show a monoclinic crystal structure when films were deposited at 400°C. Films were subjected to ex-situ furnace anneal and compared with as deposited films using XPS that showed a significant interfacial silicon dioxide growth. Hafnium silicate films were deposited by both thermal and plasma enhanced MOCVD using SiH@sub 4@ as the Si precursor. Plasma excitation improved Si incorporation resulting as much as 21.5 at.% Si. The films were subjected to furnace anneals up to 1100°C in oxygen and XPS analysis was done to confirm the silicate formation, composition and stability. Surface and bulk film morphology was studied using AFM and XRD respectively. Thermally grown Hf silicates had a measured 1.1 nm rms roughness, while plasma deposited films had 5.2 nm rms roughness. Both thermal and plasma deposited Hf silicates are amorphous as deposited, however thermal films exhibit crystallinity after a 30 min 1100°C furnace anneal in oxygen while plasma deposited films remained amorphous after the same treatment. Reflection FTIR measurements were performed and results show no evidence of bulk carbon incorporation. In-situ anneals in Ar ambient were done on thin films of HfO@sub 2@ and silicates and their change in chemical state was studied using XPS.