Arrays of micromachined hotplates have been used for materials processing on a microscopic scale. The temperature of individual elements ‘‘micro‐hotplates’’ of an array is controlled by addressing a given element with a specified current and measuring the temperature from a resistance change. This unique temperature control capability has been exploited to deposit SnO2 overlayers onto micro‐hotplates with individually controlled temperatures using reactive sputter deposition and organometallic chemical vapor deposition. Post‐deposition heating in vacuum was used to alter the stoichiometry of films. The result is an array of separately, but simultaneously, processed films. The micro‐hotplates have excellent thermal isolation from other devices (transistors, logic elements) on the chip. Electrical contact pads allow for in situ electrical characterization of the films. The use of micro‐hotplates allows high‐temperature growth to occur on portions of a silicon substrate, while other portions remain at room t...