Suppression of substrate crosstalk in mixed-signal complementary MOS circuits using high-resistivity SIMOX (Separation by IMplanted OXygen) wafers

We investigated the effectiveness of high-resistivity SIMOX (Separation by IMplanted OXygen) wafers to suppress substrate crosstalk. Small- and large- signal crosstalk measurements yielded similar results, which indicated that the frequency dependence of both types of crosstalk could be understood by analyzing the small-signal data. With the measured data, we constructed a model of substrate crosstalk with lumped elements, and found that the model described substrate crosstalk accurately. We also measured the crosstalk b etween actual digital and analog circuits. The measured and calculated data showed that high-resistivity SIMOX wafers could reduce substrate crosstalk by 5-10 dB in mixed-signal complementary metal-oxide-semiconductor (CMOS) circuits. Hence, we concluded that using high-resistivity SIMOX wafers was an effective way to suppress substrate crosstalk in mixed-signal CMOS circu its.