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

TL;DR

This paper presents a novel APAM process integrated into standard silicon transistor manufacturing, enabling atomic-scale doping control compatible with existing fabrication workflows, and demonstrating its potential for new device development.

Contribution

It introduces a compatible APAM process that can be integrated into middle-of-line silicon fabrication, expanding access and enabling new device concepts.

Findings

APAM doping density exceeds solid solubility limit

The process preserves atomic precision while being compatible with manufacturing

APAM module adds resistance without affecting transistor operation

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 that 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.