CMOS foundry implementation of Schottky diodes for RF detection

Schottky diodes for RF power measurement were designed and fabricated using a commercial n-well CMOS foundry process through the MOSIS service. The Schottky diodes are implemented by modifying the SCMOS technology file of the public-domain graphics layout editor, MAGIC, or by explicitly implementing the appropriate CIF layers. The modifications allow direct contact of first-layer metal to the low-doped substrate. Current-voltage measurements showed that only the n-type devices had rectifying properties with a barrier height of 0.78 eV. The I-V results were verified by performing capacitance-voltage measurements on diodes of different contact-areas. The diodes were tested in an RF detector circuit. The cut off frequency of the detector was shown to be 600 MHz.