Effects of slow highly charged ion irradiation on metal oxide semiconductor capacitors

Abstract

Measurements were performed to characterize and better understand the effects of slow highly charged ion (HCI) irradiation, a relatively unexplored form of radiation, on metal oxide semiconductor (MOS) devices. Si samples with 50 nm SiO 2 layers were irradiated with ion beams of Ar Q+ (Q = 4, 8, and 11) at normal incidence. The effects of the irradiation were encapsulated with an array of Al contacts forming the MOS structure. High frequency capacitance-voltage (CV) measurements reveal that the HCI irradiation results in stretchout and shifting of the CV curve. These changes in the CV curve are attributed to dangling Si bond defects at the Si/SiO 2 interface and trapped positive charge in the oxide, respectively. Charge state dependencies have been observed for these effects with the CV curve stretchout having a dependence of Q ∼1.7 and the CV curve shifting with a dependence of Q ∼1.8 . These dependencies are similar to the results of previous studies focused on the Q-dependence of the stopping power of HCIs. Published by the AVS.