Process for producing a buried isolation layer in a semiconductor substrate by implantation

Claim 2

Process for the production of a buried insulating layer (14) in a semiconductor substrate (2) in which will be formed the active zones of the active components of an integrated circuit comprising producing a mask on the regions of the substrate in which the active zones will be formed and implanting the ions (10) of oxygen or nitrogen in the substrate (12) through the mask (6, 8) for forming, by lateral dispersion and diffusion (F) in said substrate of the ions, of a continuous insulating oxide or nitride layer (14) buried in said substrate (2), the energy and implantation dose being respectively at least equal to 200 keV and 10 18 ions/cm 2 . heating the substrate during implantation (10) in order to facilitate said diffusion and performing, following implantation, an annealing of the implanted substrate (2) serving to reinforce, by lateral diffusion of the implanted ions, the continuity of the insulating layer (4) and recrystallizing from said regions of the substrate those parts of the substrate disturbed during implantation (10).

Claim 3

Process according to claim 1, characterized in that the mask has a width between 0.5 and 5 µm.

Claim 4

Process according to claims 1 or 2, characterized in that the implantation energy varies from 200 to 1 000 keV.

Claim 5

Process according to any one of the claims 1 to 3, characterized in that the implantation dose varies from 10 18 to 3 - 10 18 ions/cm 2 .

Claim 6

Process for producing a buried continuous insulating layer according to any one of the claims 1 to 4 for producing an active component of an integrated circuit on an insulating support, characterized in that it comprises the following stages : - producing an oxide layer (4) on substrate (2) constituting the gate oxide of the component, - deposition on the gate oxide layer (4) of a conductive layer (6) for producing the gate electrode of the component, - deposition on the conductive layer of an insulating layer (8), - etching the deposited insulating layer (8) and then etching the conductive layer (6) in order to produce the gate of the component, - ionic implantation (10) of oxygen or nitrogen in the substrate to form, by lateral dispersion and diffusion (F) in said substrate (2) of implanted ions, a continuous oxide or nitride insulating layer (14) or which is buried in said substrate (2), the etched conductive layer (6) and the etched insulating layer (8) serving as a mask for said implantation, - heating the substrate during ionic implantation (10), and - annealing the substrate after implantation.

Claim 7

Process according to any one of the claims 1 to 5, characterized in that the substrate (2) is made from monocrystalline silicon.

Claim 8

Process according to claim 6, characterized in that the conductive layer (6) is a polycrystalline silicon layer.

Claim 9

Process according to claims 6 or 7, characterized in that the deposited insulating layer (8) is a silicon oxide or silicon nitride layer.

Claim 10

Process according to any one of the claims 1 to 8, characterized in that annealing is carried out at a temperature between 1 000 and 1 200 °C.