CMOS Technologies
Reliability and Radiation Effects on Advanced CMOS Technologies



Permanent radiation effects in advanced CMOS technologies is one of the key focus of our studies:

You can also see our past research in this area.

Microdose Effects

We study the microdose effects induced by heavy-ion strikes on decananometer Silicon On Insulator (SOI) transistors.
Recently, we have investigated the immediate and long-term effects of heavy-ion strikes on 65-nm Fully Depleted SOI MOSFETs with different strain engineering solutions. Some of the phenomena already present in bulk devices, such as drain current collapse, are still observed alongside some new long-term effects concerning the degradation kinetics under electrical stress. On the other side, early breakdown seems to vanish. SOI degradation after heavy-ion strikes and during following electrical stress is shown to depend on the strain level and strain-inducing technique. Currently, we are working on the microdose and breakdown effects induced by heavy-ions strikes on sub 20-nm Triple-Gate SOI FETs with ultra-thin high-k gate oxide and different strain-inducing techniques, highlighting the role of material and three-dimensional architecture in the response to heavy ions.

Total ionizing dose effects

Total Ionizing Dose is one of our main activity in advanced CMOS technologies employed in space applications or in High Energy Physics (HEP) experiments. We collaborate actively with the CERN microelectronics group in order to study the effects of radiation at the extremely high doses featured by particles colliders. TID influences the Time To Dielectric Breakdown producing damage in the gate oxide and at interfaces. We are currently working on a test chip provided by CERN, which contains transistors designed to measure time to breakdown (TTDB). We performed stress after irradiation in order to investigate the dependence of TTDB on irradiation bias, temperature.
We also collaborate with IMEC, one of the major European semiconductor research laboratory that provides us dedicated structures designed to better clarify some reliability aspects. We are currently working on deep submicron CMOS transistors designed with different metal layouts, to study dose enhancement phenomena with X-rats.

Single event gate rupture

We study destructive single event effects on gate oxides exposed to heavy ions. We carried out Single Event Gate Rupture (SEGR) experiments on CMOS capacitors manufactured by different commercial foundries, focusing on the impact of bias during irradiation, substrate type, cell geometry. We are currently working on different SEGR experiments in order to better clarify if accumulation or inversion is the worst-case condition during heavy ions exposure. Moreover the geometry cell is under investigation in order to understand if edge defects may influence SEGR occurrence.
A parallel work is going to start on new test chip with transistor-based capacitor that replicate more accurately the real SEGR event on actual transistors.

Past Research

Radiation Induced Leakage Current (RILC) and Radiation Soft Breakdown (RSB) have been observed and studied for the first time by our group.




Microdose effects can significantly alter the parameters of FinFETs.


RILC (Radiation Induced Leakage Current) and RSB (Radiation Soft Breakdown) have been observed for the first time by our group.