Formimg local semi-insulating regions on silicon wafers by proton bombardment

High-resistivity silicon substrates are desirable for mixed-mode and RF integrated circuits, as it damps the substrate noise in the former and provides high Q-factor inductors and low-loss resonators in the latter. Unlike GaAs, semi-insulating silicon substrates are very hard to obtain. This paper demonstrates a low-cost method that creates local semi-insulating regions in typical silicon wafers with substrate resistivity of around 10 /spl Omega/-cm. We show that local semi-insulating substrates can be formed by MeV proton bombardment of silicon wafers. The M/spl Omega/-cm resistivity substrate is ideal for RF applications and mixed mode IC applications.