This paper studies issues related with using high energy protons to create local semi-insulating silicon regions on IC wafers for device isolation and realization of high-Q IC inductors. Topics on two approaches, i.e., one using Al as the radiation mask and the other using proton direct-write on wafers were studied. It was shown that Al can effectively mask the proton bombardment of 15 MeV up to the fluence of 1017 cm-2. For the unmasking direct write of the proton bombardment, isolation in the silicon wafer can be achieved without damaging active devices if the proton fluence is kept below 1 × 1014 cm-2 with the substrate resistivity level chosen at 140 Ω-cm, or kept at 1 × 1015 cm-2 with the substrate resistivity level chosen at 15 Ω-cm. Under the above approaches, the 1 h-200 °C thermal treatment, which is necessary for device final packaging, still gives enough high resistivity for the semi-insulating regions while recovers somewhat the active device characteristics. For the integrated passive inductor fabricated on the surface of the silicon wafer, the proton radiation improves its Q value.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering