The present inventors devised unique atomic-layer deposition systems, methods, and apparatus suitable for aluminum-oxide deposition. One exemplary method entails providing an outer chamber enclosing a substrate, forming an inner chamber within the outer chamber, and introducing an oxidant into the inner chamber, and introducing an aluminum precursor into the inner chamber. The inner chamber has a smaller volume than the outer chamber, which ultimately requires less time to fill and purge and thus promises to reduce cycle times for deposition of materials, such as aluminum oxide.