Vertically-oriented immersion server with vapor bubble deflector

An immersion server includes: a first surface that is exposed when the server is submerged within a cooling liquid; and at least one vapor bubble deflector physically abutting the first surface and extending away from the first surface at an angle. The deflector divides the first surface into an upper segment and a lower segment when the server is upright. When the server is submerged, the cooling liquid surrounding the lower segment absorbs sufficient heat to evaporate and generate vapor bubbles rising to the liquid surface. The vapor bubble deflector deflects the rising vapor bubbles away from the surface of the upper segment. This enables superior liquid contact with heat dissipating components at the upper segment and better cooling of those components. The deflector can be a device-level deflector separating two or more components or a component-level deflector separating a lower segment from an upper segment of a single component.