A self-heating electrochemical cell with nine decades of programmable linear resistance

TL;DR

This paper presents a programmable, non-volatile resistor with nine decades of linear resistance, enabling high-fidelity analog processing and in-memory computing with improved stability and efficiency.

Contribution

Introduction of a tunable, non-volatile resistor with linear I-V characteristics over nine orders of magnitude, using an electrothermal gate for large, stable resistance states.

Findings

Achieved high-precision resistance states spanning nine orders of magnitude.

Demonstrated high-fidelity analog signal processing such as amplification and multiplication.

Showed retention of analog levels with less than 1% loss over 2 months across 100 devices.

Abstract

A programmable linear resistor with a compact footprint would have profound implications for microelectronics, enabling efficient in-sensor analog signal processing and in-memory computing. Non-volatile memory offers a potential solution but suffers from limitations due to the programming mechanisms that confine switching to nanoscale constrictions or field-sensitive semiconductor junctions, leading to non-linear current-voltage relationships and errors. Here, we introduce a tunable resistor that is programmed into non-volatile, high-precision resistance states spanning nine orders of magnitude, with linear current-voltage characteristics across the entire range -- significantly improving the performance and widening the application space of resistive memory. A key advance is an electrothermal gate that simultaneously spreads heat and electrochemical reactions during programming to enable large, bulk composition modulation. The volumetric modulation can host thousands of linear resistance states with 100x lower conductance errors than other memory. This enables direct processing of analog signals with high fidelity, and we demonstrate variable-gain amplification, division, and multiplication. Integration with CMOS is used to show resilience to electrical and thermal disturb in arrays and to demonstrate retention of analog levels at <1% average loss for more than 2 months across 100 devices. Simulations indicate matrix multiplication efficiency could approach >1,000 TOPS/W.