Substrate treatment

To obtain monolayer growth control, substrates with well-defined surfaces are required. Typical mechanical and chemical polishing methods lead to a smooth substrate surface, but cannot control the structure on an atomic level. Commonly used substrates are perovskite (ABO3) complex oxides, for which the surface of as-received substrates is mixed terminated, with both AO and BO2 terminating crystal planes, without well-defined terrace steps.

The characteristics of the substrate surface is known to strongly influence the characteristics and properties of subsequently grown films. Therefore, having a welldefined surface is a prerequisite for atomic growth control. TSST offers a special treatment service, using chemical treatment and subsequent anneal steps for SrTiO3, which is the most commonly used complex oxide substrate. This treatment ensures TiO2 single termination with unit cell height and well defined terraces. Also treatment services for other widely used substrates such as LaAlO3, or NdGaO3, can be offered

TSST performs these treatments on a routine base in close co-operation with several companies specialised in the production of single crystal substrates. The treated substrates can be obtained via these companies, but TSST also offers this service for research laboratories that supply their own substrates.

The substrates can be delivered accompanied by an Atomic Force Micrograph (AFM) of their surface structure. When an AFM has been made of the surface, the exact miscut angle can be determined based on this measurement. The miscut angle determined by this method is within 0.01° from the value determined by X-Ray Diffraction.

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