Hurley, PK,Cherkaoui, K,O'Connor, E,Lemme, MC,Gottlob, HDB,Schmidt, M,Hall, S,Lu, Y,Buiu, O,Raeissi, B,Piscator, J,Engstrom, O,Newcomb, SB;

2008

August

Journal of the Electrochemical Society

Interface defects in HfO2, LaSiOx, and Gd2O3 high-k/metal-gate structures on silicon

Validated

()

HIGH-K DIELECTRICS CHEMICAL-VAPOR-DEPOSITION BOND-TYPE DEFECTS P-B CENTERS SI(111)/SIO2 INTERFACE STACKS TRAPS PASSIVATION MOBILITY STATES

155

13

20

In this work, we present experimental results examining the energy distribution of the relatively high (> 1 X 10(11) cm(-2)) electrically active interface defects which are commonly observed in high-dielectric-constant (high-k) metal-insulator-silicon systems during high-k process development. This paper extends previous studies on the Si(100)/SiOx/HfO2 system to include a comparative analysis of the density and energy distribution of interface defects for HfO2, lanthanum silicate (LaSiOx), and Gd2O3 thin films on (100) orientation silicon formed by a range of deposition techniques. The analysis of the interface defect density across the energy gap, for samples which experience no H-2/N-2 annealing following the gate stack formation, reveals a peak density (similar to 2 X 10(12) cm(-2) eV(-1) to similar to 1 X 10(13) cm(-2) eV(-1)) at 0.83-0.92 eV above the silicon valence bandedge for the HfO2, LaSiOx, and Gd2O3 thin films on Si (100). The characteristic peak in the interface state density (0.83-0.92 eV) is obtained for samples where no interface silicon oxide layer is observed from transmission electron microscopy. Analysis suggests silicon dangling bond (P-bo) centers as the common origin for the dominant interface defects for the various Si(100)/SiOx/high-k/metal gate systems. The results of forming gas (H-2/N-2) annealing over the temperature range 350-555 degrees C are presented and indicate interface state density reduction, as expected for silicon dangling bond centers. The technological relevance of the results is discussed. (c) 2007 The Electrochemical Society.

DOI 10.1149/1.2806172