  We report the fabrication and electrical characterization of depletion-mode
quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use
fixed charge in a SiO$_2$/Al$_2$O$_3$ dielectric stack to induce a 2DHG at the
Si/SiO$_2$ interface. Fabrication of the gate structures is accomplished with a
single layer metallization process. Transport spectroscopy reveals regular
Coulomb oscillations with charging energies of 10-15 meV and 3-5 meV for the
few- and many-hole regimes, respectively. This depletion-mode design avoids
complex multilayer architectures requiring precision alignment, and allows to
adopt directly best practices already developed for depletion dots in other
material systems. We also demonstrate a method to deactivate fixed charge in
the SiO$_2$/Al$_2$O$_3$ dielectric stack using deep ultraviolet light, which
may become an important procedure to avoid unwanted 2DHG build-up in Si MOS
quantum bits.
