Microsecond non-melt UV laser annealing for future 3D-stacked CMOS

TL;DR

This paper demonstrates microsecond UV laser annealing for 3D-stacked CMOS, achieving high carrier concentration with minimal resistance increase, enabling new integration possibilities in advanced semiconductor manufacturing.

Contribution

It introduces a novel application of microsecond UV laser annealing for solid phase epitaxial regrowth in 3D CMOS, with promising electrical results.

Findings

Achieved >1 x 10^21 at./cm^-3 carrier concentration

Only 5% increase in sheet resistance after UV-LA

Potential for integrating UV-LA at various 3D CMOS stages

Abstract

Three-dimensional (3D) CMOS technology encourages the use of UV laser annealing (UV-LA) because the shallow absorption of UV light into materials and the process timescale typically from nanoseconds (ns) to microseconds (us) strongly limit the vertical heat diffusion. In this work, us UV-LA solid phase epitaxial regrowth (SPER) demonstrated an active carrier concentration surpassing 1 x 10^21 at./cm^-3 in an arsenic ion-implanted silicon-on-insulator substrate. After the subsequent ns UV-LA known for improving CMOS interconnect, only a slight (about 5%) sheet resistance increase was observed. The results open a possibility to integrate UV-LA at different stages of 3D-stacked CMOS.