PROCEDE DE REALISATION D'UN TRANSISTOR A EFFET DE CHAMP A CANAL SIGE PAR IMPLANTATION IONIQUE

摘要

The method comprises: providing a substrate of semiconductor on insulator type comprising a support (1), an electrically insulating film (2), a crystalline silicon film (3), and a protection layer (4), where the crystalline silicon film has a thickness of 4-8 nm; implanting germanium ions in the crystalline silicon film through the protection layer so as to form an amorphized area that is present in contact with the protection layer that is superposed on a crystalline layer that is present in contact with the electrically insulating film; and annealing the silicon film. The method comprises: providing a substrate of semiconductor on insulator type comprising a support (1), an electrically insulating film (2), a crystalline silicon film (3), and a protection layer (4), where the crystalline silicon film has a thickness of 4-8 nm; implanting germanium ions in the crystalline silicon film through the protection layer so as to form an amorphized area that is present in contact with the protection layer that is superposed on a crystalline layer that is present in contact with the electrically insulating film; and annealing the silicon film so as to re crystallize the amorphized area from the crystalline area and to form a silicon-germanium alloy area with a first germanium concentration. A quantity of germanium ions implanted in the crystalline silicon film is arranged to form a silicon-germanium area comprising 5-45% of germanium. The method further comprises covering the crystalline silicon film by a masking pattern that is arranged to prevent introduction of the germanium ions into an area covered by the masking pattern. The protection layer comprises: a first area having a first composition and/or a first thickness; and a second area having a second composition and/or a second thickness that is different from the first composition and/or the first thickness. The annealing step forms a first silicon-germanium alloy with the first germanium concentration and a second silicon-germanium alloy with a second germanium concentration that is different from the first concentration. The first silicon-germanium alloy is covered by the first area of the protection layer and the second silicon-germanium alloy is covered by the second area of the protection layer. The substrate comprises a gate electrode, which is formed above the crystalline silicon film. The implantation of germanium ions is performed with an energy of 2-6 keV and a tilt angle to form a silicon-germanium conduction channel, silicon-germanium source and drain electrodes, and a silicon conduction channel, at a dose of 5x 10 1> 4> to 5 x 10 1> 6> cm -> 2>. A thickness of the crystalline silicon film is 3-8 nm. The protection layer has a thickness of 4-10 nm.