Probing Dopant‐Induced Quantum Dots in High‐Concentration Codoped Silicon‐On‐Insulator Thin‐Film Transistors

Codoping of silicon‐on‐insulator (SOI) thin films introduces new properties relevant for controlling transport of carriers in nanodevices. In this work, we first show how X‐ray photoelectron spectroscopy (XPS) measurements can reveal the presence of phosphorus (P) and boron (B) dopants in such codoped SOI films, before and after sputtering. We then demonstrate quantum‐dot (QD) behavior in high‐concentration codoped SOI‐FETs (field‐effect transistors) fabricated using complementary metal–oxide–semiconductor (CMOS)‐compatible processes. P‐donors ( N D ≈ 2.0 × 10 20 cm −3 ) and B‐acceptors ( N A ≈ 5.3 × 10 19 cm −3 ) were introduced into the SOI layer at a P:B ratio of 4:1 to examine how partial compensation influences dopant‐induced QD formation. Low‐temperature transport measurements on narrow‐channel devices revealed single‐electron tunneling (SET) features, including periodic current oscillations and well‐defined Coulomb diamonds, consistent with QDs formed by donor clusters influenced by acceptor‐induced potential modulations. Additionally, by tuning the back‐gate voltage, we modulated the QD potential landscape, demonstrating that vertical electric fields provide an additional degree of control over wavefunction localization and tunneling dynamics. Statistical simulations confirm that the random donor–acceptor distribution yields a finite number of uncompensated donor clusters, which can couple to form active QDs.