MOS field effect transistors for UHF applications

Three different techniques for the fabrication of UHF MOSFET's were developed and their suitability as a production process was examined. The source and drain regions were realized by phosphorus ion implantation followed by selective oxidation, by diffusion from P and As doped oxides (PDO), and by a double lateral diffusion process. In order to characterize the fabricated MOSFET tetrodes, S parameters at high frequencies (800 MHZ) were measured. The best results were obtained with elements which were manufactured using the PDO technique. A one-dimensional small signal MOS model was derived which is able to describe the static characteristics of short channel MOS transistors.