Radiation Effects and Low-Frequency Noise of III-V/III-N Semiconductor Devices
To extend Moore’s law, transformative changes have been implemented to maintain device scaling. In this dissertation, I focus on the state-of-the-art technologies for future logic and RF applications. The semiconductor devices evaluated in this work include an alternative semiconductor channel (InGaAs or GaN), high-k dielectrics, and a special device structure, i.e., FinFET or MOSHEMT structure. Due to the desire to use advanced technologies in space environments, most of the work is focused on the total-ionizing-dose (TID) radiation response and low frequency noise performance. DC characteristics and front-end-of-line reliability has also been investigated in these state-of-the-art devices. The TID responses in 16 nm InGaAs nMOS FinFETs have been evaluated. Radiation-induced trapped positive charge dominates the TID response of InGaAs FinFET transistors, with the worst case response at short gate-length devices under negative gate bias. 1/f noise measurements indicate a high trap density and a non-uniform defect-energy distribution, consistent with a strong variation of effective border-trap density with surface potential. Changes to the gate dielectric and sub-fin buffer layers significantly improve the subthreshold leakage and radiation tolerance of the modified InGaAs FinFETs. Removing tungsten from the gate stack reduces interface dose enhancement. For the GaN-based devices, the DC characteristics, reliability performance and 1/f noise results are presented. The DC and low frequency noise performances are compared among MOSHEMT, MOSFET, and HEMT structures. MOSHEMT is identified as the most robust device architecture, because it satisfies most of the DC reliability requirements for GaN-RF applications, due to the presence of a barrier layer alleviating the impact of certain degradation mechanisms.