RADIATION HARDENING FOR LOCOS WITH SALICIDE
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Dec-07
Behavior of semiconductor devices can be altered significantly by exposure to ionizing radiation. Dur- ing irradiation, electron-hole pairs are generated in the semiconductor, and in any dielectrics used, such as isolation or gate oxides. Charge generated in the dielectric can become a particular problem. While the generated electrons are swept out of the dielectric and recombine fairly rapidly, the less mobile holes remain, causing a build up of positive charge. For a PMOS device, this charge build up results in, among other effects, higher device and field thresholds. In the NMOS device, however, this charge tends to lower the device threshold, plus can also create a parasitic n- channel in the P- well under the field oxide, shorting the Nt source and drains to the N-well or substrate.