Parasitic-Aware Modelling for Neural Networks Implemented with Memristor Crossbar Array

Abstract

This paper presents a parasitic-aware modelling approach called αβ-matrix model for the simulation of neural network (NN) implemented with memristor crossbar array. The line resistance, which is the key parasitic in a memristor crossbar array is analyzed and incorporated into the model. The proposed method estimates the line resistance IR drop with computation complexity of O(mn), in contrast to O(m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) required by the classical matrix based Kirchhoff's Current Law (KCL) equations solver. The impact of the crossbar array parasitics to the vector-matrix multiplication (VMM) computation and multi-layer NN classification accuracy are also analyzed. The advantages of the proposed parasitic-aware model are demonstrated through an example of 2-layer perceptron implemented with resistive random access memory (RRAM) crossbar array for MNIST written digits classification. 97.3% classification accuracy is achieved on 64×64 6-bit RRAM crossbar arrays. Compared to the KCL solver, the classification accuracy degradation is less than 0.4% with line resistance up to 4.5Ω.