For the fabrication of (Heusler) thin films, two UHV sputtering systems are available. The smaller system (Figure 1, sputter 1) contains four (2-inch-diameter) magnetron sources in confocal geometry that can be used in DC and RF modes. Figure 5a shows a drawing of this system. The base pressure is <2 × 10−9 mbar. A co-depostion from elementary and binary targets allows us to prepare a numerous new compounds of promising novel materials in a reasonable time without having to purchase new sputtering targets with optimised composition. Alternatively, compositional gradients can be created by adjusting the tilt angle and distance of the magnetrons.
As illustrated in Figure 2, the target-to-substrate distance can be varied between 15 and 25 cm when changing the angle of the magnetrons to the substrate normal from 11° to 7°. The substrate holder can be rotated during the deposition for homogenous film growth over a maximum substrate size of 2 inches. The maximum reachable substrate temperature is 1000°. The substrate and the magnetrons contain individual shutters. This allows plasma ignition during the process without contaminating the sample. Additionally, a step-motor-driven linear shutter allows the growth of layers with a thickness gradient. All processes are computer controlled to guarantee maximum reproducibility. The samples can be transferred to this chamber either by the attached load lock system or via the long linear transfer line that is connected to the opposite position of the load lock. The additional load lock chamber preserves the independent availability of this system.