Abstract: Installation for treatment of materials for semi-conductors, starting from slices (30) gathered onto carriers (5) and treated in a series of vacuum chambers. The installation is in modular form, each module (A, B, C, D) including a straight tubular portion (1, 2, 3, 4) which forms with the adjacent modules a continuous tunnel for straight flow of the carriers (5). The carriers are driven and the slices are individually manipulated between the carriers and the treatment apparatus. The invention is applicable to treatment by epitaxis by molecular jets.