GaAs foundry services-what they offer and what they require from a customer

A GaAs foundry service allows external users access to a GaAs wafer processing facility. The users can then create their own designs using proven MESFET, HEMT or HBT based processes. Not all possible circuits or combinations of circuits are already available in MMIC form, indeed with the constant improvement of processes it is unlikely that they ever will be. Therefore, though many MMICs are available off the shelf, we often find that they are not quite what the customer is looking for. The customer may require a slight tweak to a well established design or possibly they may wish to try something quite novel. Alternatively the customer may wish to combine a number of proven designs on a single MMIC in order to develop their own customised multifunction chip solution. It is under these circumstances that an individual may decide that they would like to contact one of Europe´s GaAs foundries. Each foundry will supply the user with a manual which briefly describes the important aspects of the foundry service. This can range from the processes themselves to a list of the PCM (Process Control Monitor) limits of the specified parameters used for releasing the wafer. More importantly, these days, joining a foundry will give you the tools which will allow you to create your design. The foundry will provide you with both layout and model libraries, or indeed SMART libraries which combine the two. Once the customer has received these libraries, along with the appropriate commercially available CAD packages, they can begin their designs