A sputter unit is introduced comprising a housing, a gas inlet, an interface for removable connecting the sputter unit to a vacuum chamber, a gas outlet arranged for supplying a process gas received via the gas inlet to the vacuum chamber, an interface for removable connecting the sputter unit to a base unit comprising a vacuum pump for generating a vacuum in the vacuum chamber, and a transformer arranged in the housing for increasing a supply voltage into an ionisation voltage for ionising the process gas supplied via the gas outlet to the vacuum chamber.