An atomic layer deposition apparatus including a deposition head that is rotatably mounted around a central deposition head axis and including a susceptor having an upper surface for carrying substrates. The lower surface comprises a plurality of process sections. Each process section includes a purge gas injection zone, a first precursor gas injection zone, a gas exhaust zone, a purge gas injection zone, a second precursor gas injection zone and a gas exhaust zone. Each zone radially extends from a radially inward part of the lower surface to a radially outward part of the lower surface of the deposition head. The combination of distance between the lower surface and the upper surface, the rotational speed of the deposition head and the flow rate and the pressure of the purge gas flows are selected such that the first and second precursor gases are substantially prevented from mixing.