Hafnium oxide gate stack prepared by in situ rapid thermal chemical vapor deposition process for advanced gate dielectrics

Abstract

A high-quality HfO2 gate stack with equivalent oxide thickness (EOT) of 7.8 Å and a leakage current of Jg=0.5 mA/cm2 @ Vg=−1.0 V has been achieved by an in situ rapid thermal chemical vapor deposition process. It is found that both NH3-based interface layer and N2 postdeposition annealing are very effective in reducing EOT and leakage, and at the same time, improving film qualities. These HfO2 gate stacks show negligible frequency dependence, small hysteresis in capacitance–voltage (C–V) and weak temperature dependence of the leakage current. They also show negligible charge trapping at high voltage stress.

The structural and interfacial properties of HfO2/Si by the plasma oxidation of sputtered metallic Hf thin films

“…High-quality HfO 2 thin films have been deposited by PVD [13,14], CVD [15], Metal-organic chemical-vapor-depositon (MOCVD) [16] and atomic-layer deposition [17]. Among these deposition techniques, one of the serious problems is the interfacial layer growth due to the oxidization of the Si substrate surface, which is brought about in excess oxygen ambient at elevated temperature.…”

Hafnium oxoneopentoxide as a new MOCVD precursor for hafnium oxide films

“…Besides conventional b-diketonates such as Hf(thd) 4 (thd=2,2,6,6-tetramethyl-3,5-heptanedionate), alkoxides-Hf(O t Bu) 4 [1,12,13], Hf(mmp) 4 [3], Hf(O t Bu) 2 (mmp) 2 [3] (mmp=1-methoxy-2-methyl-2-propanolate) have also been used as precursors for MOCVD deposition of HfO 2 thin films. Alkoxides are versatile precursors for tailoring properties at a molecular level [14].…”

Degradation kinetics of ultrathin HfO2 layers on Si(100) during vacuum annealing monitored with in situ XPS/LEIS and ex situ AFM

“…Hf based dielectrics have been evaluated as the most promising candidates to replace SiO 2 as gate dielectric [1][2][3][4][5][6]. Since post-oxide-growth annealing is part of the MOS device fabrication process, the issue of HfO 2 thermal stability in contact with Si has recently received significant attention.…”