Abstract: A device (1) for homogenizing a gas distribution in a process chamber (2). The device (1) has a aperture shield (3) and a linear drive (4) for moving the aperture shield (3) in a reciprocating manner in two mutually opposite linear movement directions (5) between two terminal positions. The aperture shield (3) is able to be heated by at least one heating installation (6) of the device (1), and the aperture shield (3) by way of at least one interposed compensation element (7) of the device (1) is connected to the linear drive (4). The compensation element (7) enables a relative movement between the aperture shield (3) and the linear drive (4) in at least one direction (8) transverse, preferably orthogonal, to the linear movement directions (5) of the aperture shield (3).