Pulsed Laser Deposition (PLD) is a versatile deposition technique that has proven its value as a method for growing thin films of, e.g., ceramic materials. Over the past 20 years the technique has been improved such that currently not only simple deposition but also more fundamental applications are possible. Among these are initial growth studies, atomic layer-by-layer (MBE-like) growth, and multilayer structures. Usually such fundamental studies put severe constraints on the design and components of the deposition system.
Since different applications ask for separate specifications, every system will be custom developed. This also allows adaptations of the design to specific preferences of the customer. With the input and requirements of the customer TSST design a system that is completely tailored to the wishes of the end-user.
Twente Solid State Technology has multiple decades of combined experience in designing and constructing PLD-systems for specialized applications.
Each design is made with a maximum flexibility in mind. This allows easy variation of all possible parameters, such as target-to-substrate distance, gas mixtures, process pressure, and substrate temperature.
During the design phase possible future expansions are also taken into account. This allows the system to grow with advances and demands of future research. For example, high pressure RHEED can easily be integrated for in-situ analysis. Ion milling and sputtering tools / chambers are also commonly added for pre- and post- treatments of samples without the need for ex-situ transfer.
Twente Solid State Technology offers custom solutions to your requirements. The specifications mentioned here are not stringent and can always be adapted to meet your specific needs.
Vacuum system and gas handling
Each system consist of a metal-sealed UHV chamber, equipped with a loadlock to provide high quality vacuum. The standard base pressure of these systems is <10-8 mbar , and can be further improved with additional options.
All pump down cycles, gas inlet, and pressure control can be fully automated. To control the process pressure every gas feed has its own mass flow controller. Additional connections allow the system to be flushed with oxygen for annealing purposes or nitrogen for venting. Additional process gasses, needle valves etc. can be integrated in the design.
In order to maintain a set pressure inside the chamber both downstream and upstream control are utilized to maintain the set process pressure.
High Pressure RHEED
In principle all systems are designed to be equipped with a high-pressure RHEED facility in order to have in-situ control of the growth process. The RHEED consist of a 30keV electron gun combined with a high-pressure extension to be able to use RHEED in pressures up to 0.5 Torr. The extension will be equipped with a shut-off valve to be compatible with high-pressure, inside the chamber for annealing purposes.
A phosphorescent screen will be mounted on a tubular flange to be placed as close as possible to the substrate. Furthermore, a camera system combined with software for data acquisition is included.
A specially designed substrate heater will be implemented in the system, This heater has been optimized for low power consumption, high temperatures and compatibility with RHEED.
Most heaters can host substrates with a maximum of 1¨ diameter. (Alternatives for larger sizes are available). Substrates can be glued or clamped to the heater block
Several heating options are available, but all allow loading through the loadlock of the sample in order to maintain a low base pressure inside the system. Additionally, every heater can have 5 degrees of freedom, X, Y, Z, tilt, and azimuthal rotation.
Positioning of the heater and the temperature control can be fully automated using stepper motors and special electronics that minimize mechanical and magnetic interference with the electron beam for RHEED.