Investigation of high-quality ultra-thin LaAlO₃films as high-kgate dielectrics

Abstract

We have studied the formation of a high-quality LaAlO 3 (LAO) film directly on silicon substrates by the pulsed laser deposition method as a novel high-k gate dielectric. The LAO films can remain amorphous at temperatures up to 850˚C. An atomic force microscopy study indicated a very smooth surface of the deposited films with a rms of 0.14 nm for an 8 nm LAO film. The structures and electrical properties of metal-dielectric-semiconductor (Pt/LAO/Si) capacitors were investigated with LAO films deposited under different ambient conditions. High-resolution transmission electron microscopy indicated that interfacial reactions often occur for films of LAO deposited under oxygen ambient. A small effective oxide thickness of 1.2 nm was obtained for those films deposited under 20 Pa nitrogen ambient, with the corresponding leakage current density 17.1 mA cm −2 at +1 V gate voltage. It is proposed that amorphous LAO films are a novel promising alternative high-k gate dielectric material in future ultra-large scale integrated devices.

Combustion synthesis of LaMn1−xAlxO3+δ (0 ≤ x ≤ 1): tuning catalytic properties for methane deep oxidation

“…of 529.8 eV is consistent with the O1s binding energy of the LaAlO 3 oxide (529.9 eV). 47 The O1s signal revealed a second peak at 531.1-531.7 eV related to the adsorbed oxygen (O À /O 2 2À ) and/or carbonates/hydroxyl groups. The peak broadening and its shift to higher binding energy allow us to suggest that the concentration of OH groups probably in the form of La(OH) 3 28 and/or Al(OH) 3 increases when the Al content increases.…”

Dielectric relaxation of high-k oxides

“…Among them are cerium oxide CeO 2 [16-23], cerium zirconate CeZrO 4 [24], gadolinium oxide Gd 2 O 3 [25-27], erbium oxide Er 2 O 3 [28,29], neodymium oxide Nd 2 O 3 [30,31], aluminum oxide Al 2 O 3 [32,33], lanthanum aluminum oxide LaAlO 3 [34,35], lanthanum oxide La 2 O 3 [36], yttrium oxide Y 2 O 3 [37], tantalum pentoxide Ta 2 O 5 [38], titanium dioxide TiO 2 [39], zirconium dioxide ZrO 2 [40,41], lanthanum-doped zirconium oxide La x Zr 1 −x O 2 −δ [42,43], hafnium oxide HfO 2 [44], HfO 2 -based oxides La 2 Hf 2 O 7 [45], Ce x Hf 1-x O 2 [46], hafnium silicate HfSi x O y [47], and rare-earth scandates LaScO 3 [48], GdScO 3 [49], DyScO 3 [50], and SmScO 3 [51]. Among them, HfO 2 , HfO 2 -based materials, ZrO 2 , and ZrO 2 -based materials are considered as the most promising candidates combining high dielectric permittivity and thermal stability with low leakage current due to a reasonably high barrier height that limits electron tunneling.…”

Integrations and challenges of novel high-k gate stacks in advanced CMOS technology

“…As a result, current work related with LAO is temporarily focused on amorphous LAO films. Interfacial and microstructural properties of amorphous LAO films deposited directly on Si substrate by pulse laser deposition have been investigated by Lu et al [223]. Based on their observation, it can be seen that the LAO films can maintain amorphous at temperatures up to 850°C after rapid thermal annealing, indicating a good thermal stability of the amorphous LAO films.…”