  Solid-state devices can be fabricated at the atomic scale, with applications
ranging from classical logic to current standards and quantum technologies.
While it is very desirable to probe these devices and the quantum states they
host at the atomic scale, typical methods rely on long-ranged capacitive
interactions, making this difficult. Here we probe a silicon electronic device
at the atomic scale using a localized electronic quantum dot induced directly
within the device at a desired location, using the biased tip of a
low-temperature scanning tunneling microscope. We demonstrate control over
short-ranged tunnel coupling interactions of the quantum dot with the device's
source reservoir using sub-nm position control of the tip, and the quantum dot
energy level using a voltage applied to the device's gate reservoir. Despite
the $\sim 1$nm proximity of the quantum dot to the metallic tip, we find the
gate provides sufficient capacitance to enable a high degree of electric
control. Combined with atomic scale imaging, we use the quantum dot to probe
applied electric fields and charge in individual defects in the device. This
capability is expected to aid in the understanding of atomic-scale devices and
the quantum states realized in them.
