The low temperature STM (red arrow) can be cooled to 5K. It is ideal for single atom scanning tunneling STS because it offers a zero drift imaging environment. The machine has a differentially pumped MBE or ALD cell, argon ion source, LEED, Auger, quadrupole mass and a monochromatic angle resolved XPS. The monochromatic XPS enables determination of the oxidation states of surface atom thereby facilitating determination of bonding structures. The machine is equipped with a HV ALD dosing chamber which enables us to take decapped semiconductor samples and dose the samples with metal and oxidant precursors without air exposure.