Electrical and Thermal Dynamics of Self-Oscillations in TaO_x-Based Threshold Switching Devices

Abstract

We present experimental results of relaxation oscillations based on the TaO x threshold switching devices as a function of voltage, load resistance, and the parallel capacitance. Of particular interest are the dynamics of transitions between ON and OFF states of the device which impose an upper limit of the oscillation frequency. The dynamics have been captured by the finite element electrothermal model using only electrical conductivity vs temperature and thermally activated conductivities as input data. The model reproduced current and voltage waveforms and allowed for following the changes in current density and temperature distributions within the device during oscillations. Both undergo significant breathing-mode-type changes in each cycle as the current spontaneously constricts during the capacitance discharge/heating stage. The model points out the possible approaches toward achieving higher oscillation frequencies.

New Insights of the Switching Process in GeAsTe Ovonic Threshold Switching (OTS) Selectors

“…When the interception occurs in the NDR region, a relaxation oscillation will occur, as shown in refs. [26]. This oscillation can be explained briefly as follows.…”

“…For example, it was found that Rs defines the load line for the selector and hence its operation points and the holding current. Therefore, the selector is either switching volatilely between the static off-state and on-state, or oscillating in the transitional negative-differential-resistance (NDR) state [24][25][26][27]. Despite these early efforts, detailed experimental evidence is still lacking for characterizing the fast and sharp switching process in modern OTS devices.…”

High Amplitude Spike Generator in Au Nanodot-Incorporated NbOx Mott Memristor

“…However, if the spike amplitude is high, the amplifier can be eliminated, resulting in a more compact TRNG circuit. A widely investigated method to modulate the spike amplitude of the oscillator is through these external electrical components. , However, this method brings up a complexity issue at the circuit level. The TS behavior can be modified by controlling the device’s thermal properties, since the TS mechanism highly relies on the temperature from Joule heating.…”