Embodiments relate to a deposition device that operates in two modes: a deposition mode, and a cleaning mode. In the deposition mode, modular injectors inject materials onto a substrate to form a layer. In the cleaning mode, the deposition device is cleaned without disassembly by injecting a cleaning gas. The injector module assembly may be cleaned in the cleaning mode by injecting cleaning gas through an exhaust for removing reactant precursor and routing the cleaning gas from the exhaust to another exhaust for removing source precursor. Alternatively, the injector module assembly is cleaned by injecting cleaning gas into a passage between an injector for injecting a source precursor and another injector for injecting a reactant precursor, and routing the cleaning gas to one of the exhausts in the cleaning mode.