For the fabrication and development of high-temperature superconducting (HTS) thin film devices, which often require multiple layers, it is essential to have control over all parameters during growth. Until recently, the overwhelming majority of film growth was controlled manually. We have found this can often lead to error and irreproducibility. To overcome these problems we have designed and constructed an automated multitarget excimer pulsed laser deposition (PLD) system. We identify key elements of the system that can be utilised to address many of the problems currently encountered in HTS film growth. Optimisation using Robust Design techniques has also been used in the identification of principal parameters in growth of films and multilayers.

Pulsed laser deposition (PLD) of thin films is widely regarded as the best growth technique for the development of novel multilayer structures and devices; in particular, high-temperature superconducting (HTS) devices. To achieve this, it is essential to have the capability to deposit material from different targets sequentially in situ, namely without opening the deposition chamber. Here we present details of a multi-target carousel for multilayer depositions. It has been designed to allow target rotation and selection without any latching mechanisms or in-vacuum motors and is also suitable for use in automated systems. Additionally, it is robust, relatively inexpensive, compact, scalable and simple to build. Single-layer YBa 2 Cu 3 O 7−δ (YBCO) thin films grown using the multi-target carousel show no reduction in quality compared to ones grown using a single-target system. Moreover, the carousel has successfully been used to deposit Ag onto YBCO in situ to realize low-resistance YBCO-Ag-YBCO resistor structures; which would have been impossible with ex situ metallization. In addition, in situ homo-epitaxial MgO buffer layers on (100) MgO substrates prior to the deposition of YBCO have been investigated as a means of improving HTS film quality.

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