  We report electrically detected magnetic resonance of phosphorus donors in a
silicon field-effect transistor. An on-chip transmission line is used to
generate the oscillating magnetic field allowing broadband operation. At
milli-kelvin temperatures, continuous wave spectra were obtained up to 40 GHz,
using both magnetic field and microwave frequency modulation. The spectra
reveal the hyperfine-split electron spin resonances characteristic for Si:P and
a central feature which displays the fingerprint of spin-spin scattering in the
two-dimensional electron gas.
