Integrated circuits, the key components in thousands of electronic and computer products, are generally built layer by layer on a silicon substrate. One common layer-formation technique, known as chemical-vapor deposition (CVD), produces uneven layers and covers vertical surfaces poorly. An emergent technique, atomic-layer deposition, overcomes these shortcomings, but has others, such as slow deposition rates and longer than desirable cycle times, particularly as applied to deposition of aluminum oxide. Accordingly, the inventors devised unique atomic-layer deposition systems, methods, and apparatus suitable for aluminum-oxide deposition. One exemplary system includes an outer chamber, a substrate holder, and a gas-distribution fixture that engages or cooperates with the substrate holder to form an inner chamber within the outer 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.