Effects of Annealing Ambient on the Characteristics of LaAlO3 Films Grown by Atomic Layer Deposition

Abstract

We investigated the effects of different annealing ambients on the physical and electrical properties of LaAlO3 films grown by atomic layer deposition. Post-grown rapid thermal annealing (RTA) was carried out at 600 °C for 1 min in vacuum, N2, and O2, respectively. It was found that the chemical bonding states at the interfacial layers (ILs) between LaAlO3 films and Si substrate were affected by the different annealing ambients. The formation of IL was enhanced during the RTA process, resulting in the decrease of accumulation capacitance, especially in O2 ambient. Furthermore, based on the capacitance-voltage characteristics of LaAlO3/Si MIS capacitors, positive V FB shifting tendency could be observed, indicating the decrease of positive oxide charges. Meanwhile, both trapped charge density and interface trap density showed decreased trends after annealing treatments. In addition, RTA process in various gaseous ambients can reduce the gate leakage current due to the enhancement of valence band offset and the reduction of defects in the LaAlO3/Si structure in varying degrees.

Evaluation of Volatility and Thermal Stability in Monomeric and Dimeric Lanthanide(III) Complexes Containing Enaminolate Ligands

“…Lanthanide complexes of the formula Ln­(β-diketonate) 3 have very high thermal stabilities and can exhibit self-limited growth of oxides up to 400 °C. ,− However, Ln­(β-diketonate) 3 precursors are unreactive toward water and require ozone as a coreactant for oxide growth. ,− Ozone is highly reactive and causes oxidation of silicon substrates. Lanthanide cyclopentadienyl complexes also have very high thermal stabilities and water can be used as a coreactant for the growth of oxide films. ,− For example, the growth of Er 2 O 3 films with Er­(C 5 H 4 Me) 3 and water exhibits an ALD window from about 250 to 350 °C on Si(100) substrates . The growth of PrAlO 3 films using Pr­(C 5 H 4 iPr) 3 , AlMe 3 , and water shows an ALD window from about 275 to 325 °C .…”

“…ALD requires chemical precursors that are volatile, thermally stable at the deposition temperatures, and highly reactive toward a second reagent. , Many different ligands have been employed to create volatile and thermally stable lanthanide precursors for film growth by ALD . Ligands in previously reported precursors have included β-diketonate, − cyclopentadienyl and substituted cyclopentadienyl, ,− bis­(trimethylsilyl)­amide, alkoxide, , and amidinates and guanidinates. ,− Additionally, volatile lanthanide complexes containing N , N -dimethylaminodiboranate ligands have been recently reported but have not been tested in ALD growth. − Currently available lanthanide precursors have exhibited several problems in ALD growth, including the low reactivity of β-diketonate precursors toward water as a coreactant, substrate oxidation when ozone is used as a coreactant, low thermal stability, and lack of true self-limited growth. As a result, there is an ongoing need for volatile, thermally stable lanthanide precursors for ALD that address these issues.…”

Solid-Phase Epitaxy of Perovskite High Dielectric PrAlO3 Films Grown by Atomic Layer Deposition for Use in Two-Dimensional Electronics and Memory Devices

“…LnAlO 3 (Ln = La, Pr) films have been grown by ALD using a lanthanide precursor, an Al precursor, and an oxidant. ,,− La precursors for LaAlO 3 have included La amidinates and formamidinates, La­((NSiMe 3 ) 2 ) 3 , La­(thd) 3 , and La­(iPrC 5 H 4 ) 3 . Each of these precursors has limitations, including lack of self-limited growth, impurity incorporation, and variable reactivity toward water.…”