Tracking subsurface ion radiation damage with metal–oxide–semiconductor device encapsulation

Abstract

We describe measurements aimed at tracking the subsurface energy deposition of ionic radiation by encapsulating an irradiated oxide target within multiple, spatially separated metal-oxide-semiconductor (MOS) capacitors. In particular, we look at incident kinetic energy and potential energy effects in the low keV regime for alkali ions (Na 1 ) and multicharged ions (MCIs) of Ar Q1 (Q 5 1, 4, 8, and 11) incident on the as-grown layers of SiO 2 on Si. With the irradiated oxide encapsulated under Al top contacts, we record an electronic signature of the incident ionic radiation through capacitance-voltage (C-V) measurements. Both kinetic and potential energy depositions give rise to shifted C-V signatures that can be directly related to internal electron-hole pair excitations. The MCI data reveal an apparent power law dependence on charge state, which is at odds with some prior thin foil studies obtained at higher incident energies.

Comparison of Hartree–Fock and Hartree–Fock–Slater approximations for calculation of radiation damage dynamics of light and heavy atoms in the field of an x-ray free-electron laser

“…This can be achieved by adding multiphoton absorption channels and taking into account resonance effects in photon absorption as was done for x-ray ultraviolte (XUV) XFEL modeling [44]. Another prospective avenue to investigate is the energy deposition into a surface from collisions with highly charged ion beams [45]. Although the surface exposure time is usually well beyond the time scale of our model, the charge transfer occurs on the femtosecond time scale and therefore can be modeled using a rate equation approach.…”

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

“…The CUEBIT setup and basic operation have been reported in detail elsewhere, 23 and some previous results with electronic devices irradiated with the CUEBIT have also been reported. 24,25 The 12 mm × 12 mm Si/SiO 2 samples were mounted on a stainless steel platen and loaded into the CUEBIT target chamber. The base pressure of the target chamber was ∼1 × 10 −8 Torr, and the pressure in the beamline was in the low 10 −9 Torr range.…”

“…We note that this data analysis technique using 2D Gaussian fits and a correction factor has been employed to investigate V FB shifts in our previous work. 24 C. Charge state dependence Figure 6 shows the results of the analysis of the midgap to inversion stretchout data for all nine samples that were irradiated. The average difference between midgap and inversion points for the pristine sample was 0.21 V. The results in Fig.…”

“…Because our fluences appear to be in the saturation regime, we were unable to gain any useful information by investigating the rate of change in |V MG − V INV | with respect to fluence as we have done previously with V FB data. 24 As an alternative, we have calculated the average effect observed for a given charge state across all fluences. Because we are interested in the change in the stretchout, Δ|V MG − V INV |, the value of |V MG − V INV | recorded for the capacitors on the pristine sample was subtracted from the average |V MG − V INV | for a given charge state.…”

Ion transport through macrocapillaries – Oscillations due to charge patch formation

“…Multiply/Highly charged ions (M/HCIs) are unique in the field of ion-related physics as their charge state is significantly higher than the traditional singly-charged ions which dominate the field. This charge state, which is manifest as a non-negligible potential energy of the ions, can be used to modify the surface/subsurface structure of materials in ways that are distinct from other forms of radiation [1][2][3][4][5][6]. Beams of M/HCIs are obtained from sources such as Electron Beam Ion Source/Traps (EBIS/Ts) and Electron Cyclotron Resonance (ECR) ion sources in laboratories worldwide [7][8][9][10][11][12][13][14] and most recently at our own user facility for surface modification [15] as well as medical physics [16].…”