The transparent ITO/BaTiO3/ITO Resistive Random-Access Memory (ReRAM) vertically integrated with bus waveguides situated underneath is successfully realized as a ReRAM-based microdisk resonator fabricated on lithium niobate (LiNbO3) substrate. The radio-frequency sputtering technique was adopted for the subsequent depositions of the transparent ITO and BaTiO3 layers, while a proton-exchange method was utilized to fabricate the bus waveguides immersed in LiNbO3. The ReRAM-based microdisk resonator thus designed and fabricated has the novel functionality of memory and optical spectral filtering combined dually. As the ReRAM microdisk resonator is electronically switched between the two different memory states, or the high-resistance state (HRS) and low-resistance state (LRS), the output spectral observed at both the through and drop ports are noticeably shifted with one another before and after subjecting the ReRAM to a required forming process. Specifically, the spectral shift associated with the LRS state of ReRAM between the through and drop port terminal was approximately 0.4 nm, while roughly 0.6 nm was measured with the HRS state of ReRAM between the same two terminals. The resultant light wave filtering allows the spectrum of the interest to be selectively tuned as the ReRAM device dimensions are varied. Utilizing the different thin-film materials for ReRAM fabrication may also prove beneficial for spectral tuning. In light of different spectral shifts observed, the particular memory state of ReRAM could uniquely be interrogated by an optical means. Our discovery heralds a new era for realizing one of the novel optical memory devices reported to date.
In recent years many research groups have delved into the research and development of Resistive Random-Access Memory (ReRAM) which has the combined advantages of fast read/write speed, simplicity in structure, small device size and density, low activation bias voltage, low power consumption, allowably many periodic operating cycles and nonvolatile memory feature. In order to operate RRAM in an ultraviolet (UV) spectroscopic regime, the spectral transparency of electrodes and reliable device performance are keys to ensuring its continual applicability. Among the materials considered, nickel oxide (NiO) potentially has a broad perspective in optical applications due to their relatively wide bandgap, high mobility, high transparency, remarkably good electrical and optical characteristics. It is foreseeable in the future that the unique applicability of RRAM in UV will make its headway as a key component in many optoelectronic displaying products. The present study focuses on using Radio Frequency Magnetron Sputtering method to prepare NiO active layer and indium tin oxide (ITO) top electrode for the realization of RRAM devices and their current-voltage (I-V) and capacitance-voltage (C-V) characteristics are subsequently evaluated with and without the irradiation of ultraviolet light. Specifically, a series of reliability tests show that the fabricated memories have endured up to 100 switching cycles and the current contrast ratio between high (HRS) and low (LRS) resistance state at 0.1V has achieved more than two orders of magnitude. Furthermore, the retention time measurement has also demonstrated that the memory storage capability of these RRAMs remains in excellent operating condition after surviving more than 10,000 seconds of the test. Major attention is concentrated on finding out a correlation between the UV responsivity and switching characteristics for NiO RRAMs biased at low voltage. We found that the memory states associated with the RRAM of the smallest feature sizes could be toggled relatively easily by UV irradiation at the smallest size.
The integration of the transparent ITO/NiO/ITO Resistive Random-Access Memory (ReRAM) with vertically-coupled bus waveguides, which is ultimately emerged as a ReRAM-based microdisk resonator fabricated on lithium niobate (LiNbO3) substrate, is successfully realized. The transparent ITO and NiO layers are deposited by radio-frequency sputtering technique, while the bus waveguides in LiNbO3 is achieved by a proton-exchange method. The ReRAM-based microdisk resonator thus designed and fabricated have dual functionality of memory and optical spectral filtering capabilities. When the ReRAM microdisk resonator is electronically set at different memory states, that is, ReRAM is alternatively set in high-resistance state (HRS) and low-resistance state (LRS), the corresponding spectral shifts detected at both through and drop ports are noticeable different, when compared with those obtained before and after subjecting the ReRAM to a required forming process. Specifically, the spectral shift associated with the LRS state of ReRAM between the through and drop port terminal is around 4.4 nm, as compared to the spectral shift of approximately 1.7 nm that is associated with the HRS state of ReRAM between the same two terminals. The aforementioned characteristics of selective light wave filtering can be selectively tuned by varying the ReRAM device dimensions. The adoption of the different thin-film materials for the ReRAM fabrication may also play an important role in spectral tuning. Most important of all, because of different spectral shifts observed, the particular memory state of ReRAM could possibly and uniquely be interrogated by an optical means. The resultant discovery opens a new pathway in the future to the realization of one of the new optical memory devices.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.