Quench rate dependence of center formation in Er implanted Si

TL;DR

This study investigates how different quench rates during annealing influence the formation of specific Er centers in silicon, revealing that rapid quenching can selectively stabilize Si-coordinated Er centers suitable for quantum memory.

Contribution

It demonstrates that rapid quench annealing can selectively enhance Si-coordinated Er centers in Er-implanted Si, advancing quantum memory material development.

Findings

Higher quench rates suppress mixed Si/O Er centers.

Maximum quench rate enhances Si-only Er center formation.

Crystal-field splitting confirms C2v symmetry of Er centers.

Abstract

Er implanted Si (Er:Si) is a promising candidate for scalable planar quantum memory (QM) applications. Er has a preference to coordinate with O impurities, and multiple types of Er center are typically formed after a post implant anneal. Float zone Si was implanted with 1018 cm-3 Er and separate samples were annealed using a rapid quench annealing technique at 950 degC for 10 min with quench rates of 5, 23, 46, 93, 185 and 400 degC/s. The evolution of photoluminescence (PL) peaks and their associated Er centers was tracked as a function of quench rate. Across all samples, five distinct Er centers were identified. Two centers, one with mixed Si and O coordination and one with Si-only coordination, exhibited fully resolved crystal-field splitting of the 4I15/2 ground state together with 2 to 3 hot lines from the 4I13/2 excited state; fitting of crystal-field parameters for both was consistent with C2v symmetry. The mixed Si and O coordinated center was suppressed at quench rates above 185 degC/s, while the Si-only coordinated center was progressively enhanced with increasing quench rate up to the maximum of 400 degC/s. These results demonstrate that rapid quench annealing has the potential to selectively stabilize a single, Si-coordinated Er center in Er:Si, which is required for QM applications.