Adsorption of Moisture and Organic Contaminants on Hafnium Oxide, Zirconium Oxide, and Silicon Oxide Gate Dielectrics

Abstract

Hafnium oxide (HfO 2 ) and zirconium oxide (ZrO 2 ) are two high-materials having the potential to replace silicon oxide (SiO 2 ) as the gate dielectric. Atmospheric molecular contamination can affect the quality of the new gate dielectric film in a manner similar to SiO 2 . Characterization of contaminant adsorption behavior of these high-films should assist in deciding their potential for successful integration in silicon metal oxide semiconductor technology. The interaction of moisture and organics ͑in particular, isopropanol, IPA͒ as common interfacial contaminants with a 5 nm HfO 2 film deposited by atomic layer chemical vapor deposition ͑ALCVD͒, which is a trademark of ASM International͒ is investigated using atmospheric pressure ionization mass spectrometry ͑APIMS͒; the kinetics and mechanism are compared to that of ZrO 2 and SiO 2 . HfO 2 and ZrO 2 have similar moisture adsorption loading, but are significantly higher than that of SiO 2 . However, almost all the adsorbed moisture can be removed from SiO 2 and HfO 2 after a 300°C bake under nitrogen purge, whereas ZrO 2 surfaces retain 20-30% of the adsorbed moisture. Experiments with IPA show that the adsorption loading on the three surfaces has the following order: ZrO 2 Ͼ HfO 2 Ͼ SiO 2 . A multilayer model for adsorption of water and IPA is developed to understand the mechanism of interactions of contaminants with the three surfaces. Results from the application of this multilayer model to the experimental data indicate that ZrO 2 forms the strongest surfacehydroxyl ͑X-OH͒ bond.

Effect of humidity on the hysteresis of single walled carbon nanotube field‐effect transistors

“…• C bake-out [20]. This is one possibility of explaining our findings, that more moisture is desorbed from the SiO 2 than from the HfO 2 − TiO 2 − HfO 2 gate dielectric.…”

“…• C, which produces amorphous HfO 2 films [20]. On top of this gate insulator a matrix of alignment markers was deposited, using e-beam lithography and metallization of Pd with an adhesion layer of Ti.…”

High-pressure reactively sputtered HfO2: Composition, morphology, and optical properties

“…Therefore, the hydrogen and the oxygen excess in the HfO 2 films may be attributed to the affinity for the adsorption of hydroxyl ͑-OH͒ groups or moisture of the HfO 2 films. 28 In a previous study concerning the growth of TiO 2 films using the same HPRS system and the same deposition procedure ͑same sputtering parameters and Si-substrate cleaning͒, 12 similar concentrations of F, B, C, and N impurities were found. However, the H concentration was lower than 1%.…”

Electrical and chemical characterization of high pressure sputtered scandium oxide for memory applications

“…The high resolution spectrum shows the spin-orbit splitting of 2p level with the 2p 3/2 and 2p 1/2 components at about 401.3 and 405.5 eV, respectively, which are characteristic Sc 2 O 3 [12]. The O1s core-level spectrum shows an asymmetric shape which can be fitted to two components: a major one at 530.0 eV due to Sc-O-Sc bonds [12], and a minor one located at 531.6 eV, associated with OH -groups adsorbed by the film surface, in a manner similar to other high-κ materials [13]. A certain contribution to this last component could come from sub-surface O-atoms.…”