UC Santa Cruz

The specific machining process by which a thin film recipe is carried out determinesthe structure of each layer. For this reason, most precision thin films a recoated using techniques involving chemical species because of their consistent ability to form uniform structures. However, the set of chemicals that is able to form thin films is more limited than the set of its cousin’s technique of physically vaporizing a material source. Coupling this premise with the fact that it is advantageous to not expose a deposited sample to the atmosphere when transitioning from one deposition method to another, we were inspired to combine atomic layer deposition (ALD) and magnetron sputtering (SPU) within a single chamber– sputtering atomic layer augmented deposition (SALAD). By hybridizing the two techniques, SALAD is capable of both ALD’s precise delivery and SPU’s diversity of materials. To demonstrate SALAD’s structural and optical capabilities, we made seven different nanocomposites with 300 layers of aluminum oxide (AlOx) and copper (Cu) thin films. After confirming that each AlOx-Cu nanocomposite developed distinct layers without cross-contamination, we were surprised to see that the classical theory of effective medium approximation used to describe metal-dielectric optical properties did not apply to the measured spectroscopic reflectivity data.