We report on monolithic symmetric vertical microcavities formed by depositing dielectric-distributed Bragg reflectors (DBRs) by reactive electron-beam evaporation at low temperature (T). The DBRs consist of alternating TiOx and SiOx layers with a refractive index contrast of about 0.55 in the visible range. The DBRs, consisting of a very few index-contrast pairs, exhibit high peak reflectivity (93%) around 590nm with a full width at half maximum of about 160nm. The excellent compatibility of thin low-T reactive electron-beam evaporated films with a thicker cavity medium comprised of molecular organic compound, and prepared either in a single growth-run, or ex situ, opens the way for novel symmetric vertical-emitting resonators and monolithic photo- and electroluminescent microcavities.