Usage of Laser Timing Probe for Sensing of Programmed Charges in EEPROM Devices

Bidani, Liron; Baharav, Oded; Sinvani, M.; Zalevsky, Zeev

doi:10.1109/tdmr.2013.2272218

Cited by 7 publications

(3 citation statements)

References 11 publications

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“…The main tool in this technology is an IR laser beam acting as a contactless probe, applied on the IC from the backside while the IC under operation, is allowing a direct access to the active areas buried inside the silicon chip 18 , 23 for electrical measurement and imaging. This technology can be used, also, for optical reading of nonvolatile memories on a chip 24 and contactless probing of secret (cryptography) data on field programmable gate arrays 25 . Today, where the ICs production technology is around 10 nm in size, there is a great need for super-resolution in silicon microscopy.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of laser-induced tunable focusing in silicon

Shabairou

Tiferet

Zalevsky

et al. 2022

Sci Rep

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We report here on focusing of a probe IR (λ = 1.55 μm) laser beam in silicon. The focusing is done by a second pump laser beam, at λ = 0.775 μm and 30 ps pulse width, with a donut shape that is launched collinearly and simultaneously (with some delay time) with the IR beam pulse. The pump beam pulse is absorbed in the silicon and creates, temporally, a free charge carriers (FCCs) donut pattern in the silicon. Following the plasma dispersion effect, the donut FCCs shapes a complex index of refraction pattern in the silicon that serves as a sort of dynamic GRIN lens for the probe beam due to the diffusion of the FCCs towards the donut center. This lens can be tuned to its focal point by the pump-probe delay time to reduce the point spread function (PSF) of the IR probe beam. We start seeing the focusing of the probe beam at pump-probe delay time of $$\mathrm{\Delta t }\approx 100\mathrm{ ps}$$ Δ t ≈ 100 ps . The best focusing (results in PSF $$< 2\mathrm{ \mu m}$$ < 2 μ m ) was observed at $$\mathrm{\Delta t}\approx 350\mathrm{ ps}$$ Δ t ≈ 350 ps and it slowly degrades before the FCCs full recombination at $$\mathrm{\Delta t }\sim 12\mathrm{ ns}$$ Δ t ∼ 12 ns . We propose this beam shaping method to overcome the diffraction resolution limit in silicon microscopy on and deep under the silicon surface dependent on the pump wavelength and the pulse width. We also proposed this technique for direct measurement of the FCCs dynamics.

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Section: Introductionmentioning

confidence: 99%

Dynamics of laser-induced tunable focusing in silicon

Shabairou

Tiferet

Zalevsky

et al. 2022

Sci Rep

Self Cite

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“…Several successful attempts have been made to recover the presence of charge on the FGs. Some notable techniques are scanning Kelvin probe microscopy (SKPM) [14] , laser timing probe (LTP) [15] and scanning capacitance microscopy (SCM) [16,17] . In SKPM, the entire silicon needs to be removed from the back of FGT.…”

Section: Introductionmentioning

confidence: 99%

Design, modelling, and simulation of a floating gate transistor with a novel security feature

Zandipour

Madani

2020

J. Semicond.

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This study proposes a new generation of floating gate transistors (FGT) with a novel built-in security feature. The new device has applications in guarding the IC chips against the current reverse engineering techniques, including scanning capacitance microscopy (SCM). The SCM measures the change in the C–V characteristic of the device as a result of placing a minute amount of charge on the floating gate, even in nano-meter scales. The proposed design only adds a simple processing step to the conventional FGT by adding an oppositely doped implanted layer to the substrate. This new structure was first analyzed theoretically and then a two-dimensional model was extracted to represent its C–V characteristic. Furthermore, this model was verified with a simulation. In addition, the C–V characteristics relevant to the SCM measurement of both conventional and the new designed FGT were compared to discuss the effectiveness of the added layer in masking the state of the transistor. The effect of change in doping concentration of the implanted layer on the C–V characteristics was also investigated. Finally, the feasibility of the proposed design was examined by comparing its I–V characteristics with the traditional FGT.

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“…It would be preferable to measure the programmed charges on-site that will directly reveal the stored data. 2,3 Nardi et al 2 considered accuracy between 10 3 and 10 5 electrons for standard 5 V electrically erasable programmable read-only memory cells, on the basis of work done by Skorobogatov et al, 4 resulting in a 3.5 V shift in the threshold voltage. Measuring charge density involves directly probing the device on-site using physical measurement techniques and avoiding software protection against unwanted access.…”

Section: Introductionmentioning

confidence: 99%