The study of hot electron excitation at surfaces requires the deposition of ultrathin metal films. To probe the role of particle bombardment in such film excitations, homogeneous, atomically ordered, and relatively defect free thin films must be deposited in the same ultrahigh vacuum system where they will be studied. With these constraints in mind, the authors designed a compact deposition chamber that allows for in situ growth and analysis of metal layers, which are only a few monolayers. This deposition chamber is attached to the commercial variable temperature scanning tunneling microscope (STM) and has an internal volume of 500 cm(3). The target substrates for deposition are compatible with the STM design and are held in place in a specially designed clamping slot that enables low temperature growth. They used the custom built chamber to deposit Ag top layers with thicknesses between 8 and 15 nm on Si(100). Electronic and morphological characteristics of the prototype Ag/n-Si(100) devices are presented.