Electrically detected double electron-electron resonance: Exchange interaction of P donors and P_b0 defects at the Si/SiO₂ interface

We study the coupling of P_b0 dangling bond defects at the Si/SiO₂ interface and ³¹P donors in an epitaxial layer directly underneath using electrically detected double electron-electron resonance (EDDEER). An exponential decay of the EDDEER signal is observed, which is attributed to a broad distribution of exchange coupling strengths J/2π from 25 kHz to 3 MHz. Comparison of the experimental data with a numerical simulation of the exchange coupling shows that this range of coupling strengths corresponds to ³¹P-P_b0 distances ranging from 14 nm to 20 nm.