When considering “printed electronics,” the substrates of interest can vary from smooth glass to flexible polymeric supports, and even to rough paper. Relatively few standard semiconductor processes adapt readily to a wide variety of substrates. We will discuss an approach to thin-film electronics that uses the conformality of atomic layer deposition to produce good-quality metal oxide thin-film transistors on a wide variety of substrates.Deposition of the active materials is by an atmospheric pressure, roll-compatible process called spatial atomic layer deposition (SALD), and the materials deposited are metal oxides. Electrical properties of SALD-grown planar thin-film transistors include mobility above 20 cm²/V-s, high on/off ratios, and good uniformity of the deposited layers.In addition to depositing good-quality thin-film transistor layers at temperatures of 200 °C, this process allows for decent transistors at temperatures down to 100 °C, thus opening up the range of usable substrates.A novel vertical transistor geometry that exploits the conformal nature of the SALD deposition system will also be introduced. This device architecture shows good electrical properties and could provide a promising approach for both rigid and flexible substrates.