The aim of the work presented in this thesis is to fabricate an epitaxial magnetic tunnel transistor (MTT) consisting of a Niobium doped SrTiO3 collector, a La0.67Sr0.33MnO3 base, a SrTiO3 tunnel barrier and a Co emitter. The motivation is that this device is sensitive to the spin dependent scattering of hot electrons in a half-metallic ferromagnet. Further we anticipate that the high crystalline quality of the base will result in a large hot electron transmission.