Selenium implantation into GaAs for integrated circuits

To develop GaAs integrated circuits, using direct Se-ion implantation into semi-insulating substrates, it was essential to carefully characterise the electrical activation achieved for various implantation conditions to identify the various parameters which need to be understood and controlled to achieve uniformity and reproducibility. A sophisticated apparatus based on electrochemical techniques was used to determine the carrier concentration and mobility profiles. Finally, the measured profiles are related directly to the DC parameters of test FETs measured on the integrated circuit chips.