International Business Machines Corporation

Alwin E Michel

Cheng Tzong Horng

Robert Otto Schwenker

James F Ziegler

Hans S Rupprecht

John L Mauer, Iv

Laura B Rothman

Reginald F Lever

The process employs ion implantation for precise dopant control. The implantation is performed into a thin layer of amorphous silicon covering the emitter and collector opening. The implantation energy is chosen so that the damage is confined to the amorphous layer. Since the deposited silicon layer is to be removed by subsequent processing, its thickness must be carefully controlled. The layer is preferably deposited by a sputtering technique which allows the necessary uniformity and reproducibility of the layer thickness. Furthermore, the sputtering process with its energetic ions provides a reproducible quality interface which is of critical importance for a diffusion source. With such a source, the diffusion into the single crystal silicon extends about the same distance in the horizontal as the vertical direction. This provides the greatest possible horizontal displacement of the junction under the passivating silicon dioxide layer. The depths of the n-type region is thinned to the single crystal surface by consuming the polysilicon partly through oxidation and partly through conversion to platinum silicide. The platinum silicide silicon interface provides a high surface recombination velocity in order to deplete the density of holes injected into the emitter. The low hole density in the emitter region has a direct benefit of decreasing the switching delay due to hole storage in the emitter, and hence higher device performance.

Consumable amorphous or polysilicon emitter process

A planar deep oxide isolation process for providing deep wide silicon dioxide filled trenches in the planar surface of a silicon semiconductor substrate, said process comprising the steps:

Planar deep oxide isolation process utilizing resin glass and E-beam

In this process of producing a bipolar transistor, all the regions of the device except the emitter region are formed by ion implantation through an inorganic dielectric layer of uniform thickness. Subsequently, all the contact openings to the emitter, base and collector are formed and the emitter is implanted through the emitter contact opening. This unique combination of process steps permits the use of a surface insulating dielectric layer of uniform thickness, wherein all capacitances are uniform and controllable while still permitting direct implantation of the emitter, which, because of its shallow depth is difficult to implant through an oxide.

Process for producing integrated circuit devices by ion implantation

A method for forming a non-epitaxial bipolar integrated circuit comprising first forming in a silicon substrate of one-type of conductivity, recessed silicon dioxide regions extending into the substrate and laterally enclosing at least one silicon substrate region of said one-type conductivity. Then, forming by ion implantation the first region of opposite-type conductivity which is fully enclosed laterally by said recessed silicon dioxide. This region is formed by directing a beam of ions of opposite-type conductivity impurity at said enclosed silicon region at such energy and dosage levels that the opposite conductivity-type impurity introduced into the substrate in said region will have a concentration peak at a point below the surface of this first region. Then, a region of said one-type conductivity is formed which extends from the surface into said first opposite-type conductivity region to a point between said concentration peak and said surface. Next, a second region of said opposite-type conductivity is formed which extends from the surface part way into said region of one-type conductivity. Preferably, the ion beam energy level is at least one MeV, and said concentration peak is at least one micron below the surface. It is further preferable that the energy and dosage levels of the beam of ions are selected so that the opposite-type conductivity impurity has a more gradual distribution gradient between the peak and the surface than between the peak and the junction of the first region with the substrate.

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Ossining, NY, United States of America

Alwin E Michel