Process for the manufacture of a transistor

Abstract

Abstract 1. A process for manufacturing a transistor realised in a caisson of an integrated circuit laterally delimited by a deep peripheral trench, the bottom of the caisson containing a layer embedded in a semiconductor substrate having a first type of conductivity, the embedded layer having a second type of conductivity, and the process comprising the following steps : a) producing the localized embedded layer (23, 33) in the substrate (1) of the first conductivity type, at the upper side of which an epitaxial layer (2) of the second conductivity type is made to grow ; b) diffusing zones (22, 31, 32) of the first conductivity type in selected locations of the epitaxial layer in order to constitute functional layers of the transistor ; c) simultaneously digging, on the one hand, the peripheral trench (40) having an U-shaped section and completely surrounding the transistor and the embedded layer, this digging penetrating down into the substrate below the epitaxial layer outside the zone, in wich the embedded layer is present, and, on the other hand, an opening (50, 60) having an U-shaped section localized above the embedded layer and penetrating into the latter without traversing it entirely, in order to constitute an access to the embedded layer, said trench and said opening cutting the junctions between said zones and the epitaxial layer at certain locations ; d) proceeding with a thermal oxidation for laterally insulating dielectrically the trench and the opening by means of an oxide layer (41, 51, 61) ; e) proceeding with an ion implantation for rendering the bottom of the trench and of the opening selectively accessible to etching ; f) selectively etching the oxyde layer on the bottom of the trench and of the opening in view of its elimination ; g) filling the trench and the opening with a conductive substance (42, 52, 62) permitting the realisation of an electrical access to the substrate via the peripheral trench, and an electrical access to the embedded layer via the opening ; h) finalizing the structure by realising the necessary supplementary diffusions and the desired interconnections.

Inventors

• 👤 Eugène Tonnel

Bibliographic Details