Compute in memory three-dimensional non-volatile nand memory for neural networks with weight and input level expansions

Abstract

A non-volatile memory device for performing compute in memory operations for a neural network uses a three dimensional NAND architecture. Multi-bit weight values are stored encoded as sets of threshold voltages for sets of memory cells. A weight value is stored in multiple memory cells on the same word line and connected between a bit line and a source line, each of the memory cells programmed to one of multiple threshold voltages. When multiplying an input value with the weight value, the word line is biased so that, for at least one of the threshold voltages, the memory cell will be in the linear operation region. Input values are encoded as a set of one or more voltage levels applied to a corresponding set of bit lines, each bit line connected memory cells also storing the weight value, connected to the word line, and connected to the source line.