Effect of substrate bias on frequency dependence of MOSFET noise intensity

We have revealed that, using an originally-developed noise measurement system, the change in 1/f noise intensity due to a substrate bias mostly ranges in low frequencies, from 1 Hz to 100kHz. Above 100 kHz to 30 MHz, the 1/f component still continues. However, the noise intensity does not strongly depend on the substrate bias. The substrate bias alters the distance of inversion carriers from the SiO₂/Si interface. Therefore, these results indicate the possibility of separating several 1/f factors, such as the number fluctuation and the mobility fluctuation.