Monolithic and heterogeneous three-dimensional integration of two-dimensional materials with high-density vias

Abstract

Monolithic three-dimensional (M3D) integration is being increasingly adopted by the semiconductor industry as an alternative to traditional through-silicon via technology as a way to increase the density of stacked, heterogenous electronic components. M3D integration can also provide transistor-level partitioning and material heterogeneity. However, there are few large-area demonstrations of M3D integration using non-silicon materials. Here, we report heterogeneous M3D integration of two-dimensional materials using a dense inter-via structure with an interconnect (I/O) density of 62,500 I/O per mm2. Our M3D stack consists of graphene-based chemisensors in tier 2 and molybdenum disulfide (MoS2) memtransistor-based programmable circuits in tier 1, with more than 500 devices in each tier. Our process allows the physical proximity between sensors and computing elements to be reduced to 50 nm, providing reduced latency in near-sensor computing applications. Our manufacturing process also stays below 200 °C and is thus compatible with back-end-of-line integration. Tiers containing graphene-based sensors and molybdenum disulfide-based processors can be vertically stacked using a monolithic integration process, with an interconnect density of 62,500 per mm2.