Mixed-Dimensional Heterostructures Fabricated through Micro-Transfer Printing of InP Thin Films on Monolayer Graphene and MoS2: A Parameter Space Evaluation

Abstract The heterogeneous integration of semiconductor devices grows in cost as critical device dimensions are pushed to smaller scales. Micro-assembly technologies, such as micro-transfer printing ( µ TP), offer a solution as they are highly scalable and cost-effective. The µ TP approach enables efficient use of growth substrates by smart integration of transferred device “coupons” on receiving “target” substrates. This process allows the fabrication of novel device architectures with reduced critical dimensions and otherwise inaccessible heterojunction configurations, including mixed-dimensional heterostructures (MDH) of III–V semiconductors and two-dimensional (2D) nanomaterials. Here, we describe a process to release III–V device layers from as-grown source substrates before µ TP onto 2D materials. Transferrable coupons of lattice-matched InP and InAlAs thin films grown via metal–organic chemical vapor deposition (MOCVD) on InP were fabricated by deposition of a masking oxide and photolithographic patterning, followed by etching to define and release the InP coupons from the sacrificial InAlAs layer. Coupons were micro-transfer-printed onto a range of substrates including silicon, graphene, and monolayer molybdenum disulfide. To elucidate the impact of printing conditions on InP coupon transfer, a design of experiments was conducted to characterize the µ TP parameter space in terms of critical pick and print settings. Transfer printing onto low-dimensional monolayer materials can better enable site-specific, high-throughput heterogeneous integration with the high print yields demanded by scalable manufacturing and enable low complexity fabrication for diverse device applications.