How does body biasing impact noise margin in digital circuits?

Body Bias depends on how we balance speed and stability. We all know forward body bias lowers threshold voltage and gives faster operation, but it can reduce noise margin. On the other hand, reverse body bias improves noise margin but slows down the circuit. So, you have to decide: if you want more stability in memory cells, go for reverse bias; but if you want faster logic circuits, you may prefer forward bias, even with lower noise margin.

In my opinion, body biasing can sometimes reduce the noise margin if not used carefully. For instance, if you apply forward body bias to reduce the threshold voltage, the transistor becomes more sensitive to small voltage variations. That means even a small noise can make the transistor switch, which decreases the noise margin. So, you gain speed but lose noise immunity. 

Body biasing helps in improving the noise margin, especially when we use reverse body bias. For example, if you apply reverse bias to an NMOS, its threshold voltage increases, which means it won’t turn on due to small noise fluctuations. This makes the circuit more stable against unwanted switching. So, in simple words, reverse body biasing can make your circuit less sensitive to noise.