1. Materials for microwave components

The microwave performance of a semiconductor component depends partly on the physical properties of the material used, and partly on the topology of the component and the fundamental physical mechanisms governing its operation. Over the past decade, considerable progress has been made in the field of semiconductor materials and microwave components, thanks to the development of epitaxy techniques (molecular-jet and gas-phase organometallic epitaxy) and the use of ion implantation and electron-beam lithography. This has made it possible to improve the electrical performance of conventional components (bipolar transistors, diodes) and to design new components (heterojunction transistors).