Abstract: The invention relates to an encapsulating box for a semiconductor operating in the range 2 to 20 GHz.At these frequencies, existing boxes have a metal base, an insulating frame and a cover. Two input - output connections pass through the frame. A leak line forms between the input and output by stray capacitive coupling of the connections with the welding metal bands of the cover. The invention opposes this input - output coupling by metallization of the box, with reserves for resists around the connection passages. The metal film joining the welding metal films to the electrical earth of the base reflects the power taken by capacitive coupling on the connections.Insulation obtained: -30 db at 15 GHz. Application to ultra-high frequency components.

Abstract: A process allowing the position and the dimensions of the grid of a field-effect transistor as well as the gaps between source and grid, grid and drain to be fixed as early as the first masking operation. To this end, a mask is formed comprising source, grid and drain windows by using a first insulating or semi-insulating material then the three windows are filled by means of a second material. The ohmic source and drain contacts are deposited in the corresponding windows reopened by selective etching of the second material effected after masking the first part of the layer situated above the non-reopened window. Second selective etching after masking of the contacts allows a Schottky-type grid contact to be deposited.

Abstract: A component of the "hybrid-circuit" type comprising an active component, such as a very-high-frequency field-effect transistor, and a sealed housing, intended for operating as an amplifier in a large frequency band, in the range from 1 to 20 Gc/s. In this hybrid component, are accomodated in the same housing, by using in particular the ceramic elements of the base situated on the periphery of an earth return aperture containing the active component, metallizations forming lines having distributed constants. Moreover, to obtain a low standing-wave ratio on these lines, lumped circuit elements are placed inside the housing in the closest vicinity of the active component.