Silicon-Compatible Memristive Devices Tailored by Laser and Thermal Treatments

Abstract

Nowadays, memristors are of considerable interest to researchers and engineers due to the promise they hold for the creation of power-efficient memristor-based information or computing systems. In particular, this refers to memristive devices based on the resistive switching phenomenon, which in most cases are fabricated in the form of metal–insulator–metal structures. At the same time, the demand for compatibility with the standard fabrication process of complementary metal–oxide semiconductors makes it relevant from a practical point of view to fabricate memristive devices directly on a silicon or SOI (silicon on insulator) substrate. Here we have investigated the electrical characteristics and resistive switching of SiOx- and SiNx-based memristors fabricated on SOI substrates and subjected to additional laser treatment and thermal treatment. The investigated memristors do not require electroforming and demonstrate a synaptic type of resistive switching. It is found that the parameters of resistive switching of SiOx- and SiNx-based memristors on SOI substrates are remarkably improved. In particular, the laser treatment gives rise to a significant increase in the hysteresis loop in I–V curves of SiNx-based memristors. Moreover, for SiOx-based memristors, the thermal treatment used after the laser treatment produces a notable decrease in the resistive switching voltage.

Electrical Characteristics of CMOS-Compatible SiOx-Based Resistive-Switching Devices

“…Figure 4 shows an HR X-TEM image of a SiO x -based memristive device after the thermal treatment. According to Figure 4 , the SiO x film has an amorphous structure with nanocrystals identified as Zr 3 O (area 1) and ZrO 2 (area 2) through a comparison of the interplanar spacings in the HR X-TEM image with the literature data performed earlier [ 8 ]. Such nanocrystals can form during thermal treatment due to a partial oxidation of the top electrode layer and can play a positive role in the localization of conductive filaments, e.g., as electric field concentrators [ 13 ].…”

“…The absence of changes in R s at high frequencies indicates the absence of electrochemical processes leading to a change in resistance in the top electrode. Earlier, the thermal treatment of memristive stacks was shown to result in an irreversible change in their electrical characteristics and to positively affect the resistive switching performance of these stacks positively in some cases [8]. Because the memristive stacks under study did not demonstrate stable resistive switching in the initial state, they were subjected to thermal treatment in dried air ambient in a sealed thermostat at 250 °C for 10 min.…”

“…The SiO x films with a nominal thickness of 13 nm were deposited onto standard factory-made TiN(25 nm)/Ti(25 nm)/SiO 2 (500 nm)/Si(001) substrates using the PECVD method. The parameters of the deposition process were described elsewhere [8]. Next, the Au (20 nm) top electrodes with Zr sublayers (8 nm) were deposited onto the SiO x films by direct-current (DC) magnetron sputtering at the substrate temperature 200 • C. The areas of the top electrodes were S ~10 −2 cm 2 .…”

“…The sign of the voltage applied to memristive devices corresponded to the potential of the top electrode (Au) relative to the potential of the bottom electrode (TiN). In the present study, the current–voltage ( I–V ) curves of memristive devices, as well as the small-signal frequency ( f ) dependencies of the capacitance C ( f ), of the conductance G ( f ), and of the resistance R ( f ) for the parallel and serial resistor–capacitor equivalent circuits, were studied in the LRS and in the HRS at different temperatures, as in [ 8 ]. The capacitance–voltage ( C–V ) and conductance–voltage ( G–V ) curves were also investigated.…”

Femtosecond Laser-Induced Nano-Joining of Volatile Tellurium Nanotube Memristor

“…Moreover, laser post-treatment is very promising for modifying the performance of the memristors. Koryazhkina et al reported that using laser and thermal treatment can significantly enhance the hysteresis loop in I-V curves of SiNx-based memristors and reduce switching voltage [42]. The effects were attributed to the change of positive-charge density and the annealing of surface states.…”