Direct integration of atomic precision advanced manufacturing into middle-of-line silicon fabrication

Abstract: Atomic precision advanced manufacturing (APAM) dopes silicon with enough carriers to change its electronic structure, and can be used to create novel devices by defining metallic regions whose boundaries have single-atom abruptness. Incompatibility with the thermal and lithography process requirements for gated silicon transistor manufacturing have inhibited exploration of both how APAM can enhance CMOS performance, and how transistor manufacturing steps can accelerate the discovery of new APAM device concepts. In this work, we introduce an APAM process that enables direct integration into the middle of a transistor manufacturing workflow. We show that a process that combines sputtering and annealing with a hardmask preserves a defining characteristic of APAM, a doping density far in excess of the solid solubility limit, while trading another, the atomic precision, for compatibility with manufacturing. The electrical characteristics of a chip combining a transistor with an APAM resistor show the APAM module has only affected the transistor through the addition of a resistance, and not by altering the transistor. This proof-of-concept demonstration also outlines the requirements and limitations of a unified APAM tool which could be introduced into manufacturing environments, greatly expanding access to this technology, and inspiring a new generation of devices with it.