Atomic layer deposition grown metal-insulator-metal capacitors with RuO2 electrodes and Al-doped rutile TiO2 dielectric layer

Abstract

Articles you may be interested inTEMAZ/O3 atomic layer deposition process with doubled growth rate and optimized interface properties in metal-insulator-metal capacitors J. Vac. Sci. Technol. A 31, 01A123 (2013); 10.1116/1.4766281 Improvement in the leakage current characteristic of metal-insulator-metal capacitor by adopting RuO2 film as bottom electrode Appl. Phys. Lett. 99, 022901 (2011); 10.1063/1.3609875 Influence of precursor chemistry and growth temperature on the electrical properties of SrTiO 3 -based metalinsulator-metal capacitors grown by atomic layer deposition J. Vac. Sci. Technol. B 29, 01AC04 (2011); 10.1116/1.3525280 Impact of crystallization behavior of Sr x Ti y O z films on electrical properties of metal-insulator-metal capacitors with TiN electrodes Appl. Phys. Lett. 97, 162906 (2010); 10.1063/1.3505323 Atomic-layer-deposited Al 2 O 3 -Hf O 2 -Al 2 O 3 dielectrics for metal-insulator-metal capacitor applications Appl. Phys. Lett.Metal-insulator-metal structures for dynamic random access memory capacitor applications were prepared by atomic layer deposition. Rutile TiO 2 dielectric layers were grown on top of RuO 2 electrodes. TiO 2 layers were doped in different ways by aluminum and these structures were compared to undoped ones. C-V and J-V measurements show that Al doping reduces the capacitance density of the stacks while reducing leakage current. Varying the initial Al doping profile did not change the electrical properties of the stacks. Leakage current analysis revealed that the current in the doped samples is controlled by Schottky emission.

Titanium dioxide thin films by atomic layer deposition: a review

“…These conclusions by Kim et al [551,552,554] are supported for example by the results of Hudec et al who detected Al on the film surface for a 20-nm thick film doped only in its bottom 2.5-nm part; the through-thickness Al concentration was far from constant though [130]. Apart from the higherthan-average Al content on the top surface, the depth profile of the Al concentration may also exhibit a peak at the film-substrate interface [130]. Furthermore, from XPS investigation it has been shown that Al ions form in rutile-structured films a chemically uniform Al-Ti-O film without any phase separation [551]; also, for anatase films peak shifts in Raman data have indicated that Al 3+ substitutes for Ti 4+ in the anatase lattice [650].…”

“…Moreover, first-principle calculations have indicated that Al atoms find energetically favourable positions on the surface of rutile TiO2, such that there is a driving force for Al atoms towards the film surface during the growth [552]. These conclusions by Kim et al [551,552,554] are supported for example by the results of Hudec et al who detected Al on the film surface for a 20-nm thick film doped only in its bottom 2.5-nm part; the through-thickness Al concentration was far from constant though [130]. Apart from the higherthan-average Al content on the top surface, the depth profile of the Al concentration may also exhibit a peak at the film-substrate interface [130].…”

“…The dielectric performance observed appears to be rather independent of the ALD process used, such that aside of the original Ti(O i Pr)4/AlMe3/O3 route [551,552,554], e.g. the Ti(O i Pr)4/AlMe3/H2O [130] and TiCl4/AlMe3/H2O [186,265] routes give similar results once RuO2 is used as the substrate instead of Ru. It is worth noting that post-metallization annealing treatments for metal-insulator-metal stacks are frequently used to optimize the electrical performance.…”

Evaluating the Top Electrode Material for Achieving an Equivalent Oxide Thickness Smaller than 0.4 nm from an Al-Doped TiO2 Film

“…This means that the large difference in capacitance density in Figure 1a was not induced by the change in the bulk properties, including the possible outward diffusion of Al into the RuO 2 electrode. 13 Interestingly, a certain difference (approximately 0.1 nm) in the y-intercept between the Pt and RuO 2 TEs was observed for all the three cases: the capacitors with Pt TE showed a higher EOT than those with RuO 2 TE. This means that the interfacial layer between Pt TE and TiO 2 or ATO has a lower dielectric constant than the interfacial layer between RuO 2 TE and TiO 2 or ATO, which is the main reason for the higher capacitance density of ATO with RuO 2 TE in Figure 1a.…”

Characterization of atomic layer deposition HfO2, Al2O3, and plasma-enhanced chemical vapor deposition Si3N4 as metal–insulator–metal capacitor dielectric for GaAs HBT technology

“…26,[32][33][34] Among these films, the PECVD Si 3 N 4 is the most widely used, as it can be deposited at 300 C and is compatibility with GaAs processing, with a 60 nm film having good physical, chemical, and electrical characteristics, including a high dielectric breakdown voltage of 65 V and a breakdown field of 10 MV/cm or higher. 1,2 This PECVD Si 3 N 4 film has been used as capacitor dielectric in GaAs HBT, 1,2,35 high electron mobility transistor (HEMT), 36,37 and other monolithic microwave integrated circuits (MMIC) 18,38 technologies.…”