Studies of ionizing radiation effects in nanoscale CMOS technology nodes

Description

X-ray radiation damage of semiconductor devices originates from radiation-induced fixed charge in the insulating regions and interface traps [1]. Device arrays fabricated in 28 nm bulk CMOS with pMOSFET and nMOSFET transistors of different dimensions have been studied. Stress tests have been performed with X-rays of energies in range 10 to 40 keV. Transfer and output characteristics have been measured before irradiation as well as after 12 steps of total ionizing dose (TID) to track evolution of device parameters. These steps start with 100 krad and 500 krad, corresponding to TID levels close to those experienced by instruments in space missions or medical imaging and reach ultrahigh levels of 900 Mrad, which is of interest for high energy physics experiments. Similarly to older technology nodes the effect of radiation induced narrow channel effect (RINCE) [2] related to traps within the shallow trench isolation (STI) is observed on device characteristics. Transistors in the 28 nm process, in contrast to technology nodes down to 65 nm already widely studied for TID effects, are equipped with high-K/metal gate. Therefore material properties and formation of traps might have to be reconsidered when interpreting the post-irradiation measurement results. TCAD device model including HfO2 - SiO2 gate stack and strained channel is adapted to measurement results. In this talk the 28nm CMOS process will be introduced and selected device parameters will be analysed with respect to radiation damage. Finally the approach of employing the model to examine various radiation damage effects observed after TID stress will be discussed.
[1] Oldham, Timothy R., and F. B. McLean. "Total ionizing dose effects in MOS oxides and devices." IEEE transactions on nuclear science 50.3 (2003): 483-499.
[2] Faccio, F., et al. "Radiation-induced short channel (RISCE) and narrow channel (RINCE) effects in 65 and 130 nm MOSFETs." IEEE Transactions on Nuclear Science 62.6 (2015): 2933-2940.

Period	26 Sep 2019
Held at	Advanced Materials Day 2019
Event type	Other
Location	Graz, Austria
Degree of Recognition	Local