Quantum wave function engineering of dopant-based Si nanostructures reveals new physics in the solid state, and is expected to play a vital role in future nanoelectronics. Central to any fundamental understanding or application is the ability to accurately characterize the deformation of the electron wave functions in these atom-based structures through electric and magnetic field control. We present a method for mapping the subtle changes that occur in the electron wave function through the measurement of the hyperfine tensor probed by (29)Si impurities. We calculate Stark parameters for six shells around the donor. Our results show that detecting the donor electron wave function deformation is possible with resolution at the sub-Bohr radius level.