Medical interventions increasingly rely on biosensors that can provide reliable quantitative information. A longstanding bottleneck in realizing this, is various non-idealities that generate offsets and variable responses across sensors. Current mitigation strategies involve the calibration of sensors, performed in software or via auxiliary compensation circuitry thus constraining real-time operation and integration efforts. Here, we show that bio-functionalized metal-oxide memristors can be utilized for directly transducing biomarker concentration levels to discrete memory states. The introduced chemical state-variable is found to be dependent on the devices’ initial resistance, with its response to chemical stimuli being more pronounced for higher resistive states. We leverage this attribute along with memristors’ inherent state programmability for calibrating a biosensing array to render a homogeneous response across all cells. Finally, we demonstrate the application of this technology in detecting Prostate Specific Antigen in clinically relevant levels (ng/ml), paving the way towards applications in large multi-panel assays.

Memristor is a promising device as a fundamental building block for future unconventional system architectures such as neuromorphic computing, reconfigurable logic, and multibit memories. Therefore, to facilitate circuit design using memristors, accurate and efficient models spanning a wide range of programming voltages and temperatures are required. In the first part of this series, we propose a behavioral model for temperature dependence of nonvolatile switching dynamics of TiO x memristors. We begin by describing pulsed resistance transients (PRTs) of the memristors and then we use a multistage methodology to establish bias and temperature dependence of the model parameters. The proposed model is then shown to accurately describe the PRT characteristics of Pt/TiO x /Au and Pt/TiO x /Pt memristors.

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The operating current regime is found to play a key role in determining the synaptic characteristic of memristor devices. A conduction channel that is formed using high current compliance prior to the synaptic operation results in digital behavior; the high current stimulus forms a complete conductive filament connecting the cathode and anode, and the high electric field promotes abrupt redox reactions during potentiation and depression pulsing schemes. Conversely, the conduction can be reconfigured to produce a filamentary-homogeneous hybrid channel by utilizing the low current stimulus, and this configuration enables the occurrence of analog behavior. The capabilities of memristors showing programmable digital-to-analog or analog-to-digital transformation open a wide range of applications in electronics. We propose a conduction mechanism to explain this phenomenon.

Environmental conditions can greatly affect the performance of semiconductor devices. Great sophistication has thus gone into developing versatile systems that allow benchmarking of operating characteristics under a variety of temperature and humidity conditions. Recently, Resistive Random Access Memory (RRAM) technologies, also known as memristors, have received a lot of attention for memory and computing applications. This interest is showcased by several reports on technology and applications developments, as well as developments on the underpinning infrastructure, i.e. models and characterization tools, that renders such technologies useful. Several international research groups and companies are nowadays using ArC One TM , a versatile instrument that allows en masse characterization of RRAM technologies, as has been presented previously in several demo sessions at ISCAS. In this work, we present a newly developed module that expands ArC One TM capabilities through incorporating an environmental control system. The proposed module condenses the functionality of significantly larger, more complex and higher cost systems into a low cost, small form-factor and user friendly desktop-operated device. The system allows for temperature, atmospheric composition and humidity control and can be used for studying the impact of such settings on the electrical characteristics of RRAM technologies.