Multidomain FeFET-Based Pixel for In-Sensor Multiply-and-Accumulate Operations

This article presents a ferroelectric field-effect transistor (FeFET)-based active pixel sensor that performs in-sensor multiply-and-accumulate (MAC) operations by leveraging the multidomain polarization states of ferroelectric layers. The proposed design integrates a programmable FeFET into a three-transistor pixel circuit, where the FeFET’s programming-voltage-controlled nonvolatile conductance encodes the weight, and the photodiode voltage drop encodes the input. Their interaction generates an output current proportional to the product, enabling in-pixel analog multiplication. Accumulation is achieved by summing output currents along shared column lines, realizing full MAC functionality within the image sensor array. Extensive HSPICE simulations, using 45-nm CMOS models, validate the operation and confirm the scalability of the design for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3$</tex-math> </inline-formula> convolution kernels. The pixel pitch is 2.295 μm (horizontal) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 2.4525 μm (vertical). The design also supports handling of negative weights, broadening its applicability to signed neural operations. This compact and energy-efficient design is well suited for real-time edge computing, neuromorphic vision, and secure sensing applications.