On the behaviour of passive guard-rings in lightly doped substrates

The effectiveness of passive guard-rings in high-frequency applications is studied using a simple approach. The results of this study reveal that while the performance of p+ guard-rings deteriorate as the frequency of operation increases, the n-well guard rings may exhibit the opposite trend. Furthermore, these results predict that n-well guard-rings can even act as p⁺ guard-rings at very high frequencies. The effect of other guard-ring parameters, such as placement and shape, on its noise suppression capability is also investigated