Hole-induced 1/f noise increase in MOS transistors

This paper presents experimental evidence for hole-generated 1/f noise traps in gate oxides near the MOS interface. To clarify the microscopic nature of noise traps, 1/f noise is measured in Si MOS transistors in which carriers are intentionally injected into the gate oxides. It was found that 1/f noise increases more rapidly after drain avalanche hot-carrier injection than after channel hot-electron injection. A rapid noise increase is also observed after X-ray irradiation. These results show that the increase in 1/f noise is closely related to holes. We propose a model in which the reaction between holes and oxygen vacancies near the interface creates noise traps, i.e., E´ centers and fixed positive charges.