International Business Machines Corporation

Arunachala Nagarajan

Steven G Barbee

James Marc Leas

James R Lloyd

Homi G Sarkary

Conrad A Barile

James S Makris

Raj K Raheja

Goerge R Goth

A process for the preparation of a semiconductor device in a thin film of a monocrystalline semiconductor material supported on the surface of a substrate. In the process a thin film of a monocrystalline semiconductor material is formed on a substrate. The film of monocrystalline semiconductor material is doped at various depths with various types and concentrations of dopants. Thereafter, contacts are established at various depths of the doped thin film. In one embodiment, a thin film of a non-monocrystalline semiconductor material is deposited on a substrate. The thin film of non-monocrystalline semiconductor material is doped in situ as it is being deposited with various doping impurities to provide various types and concentrations of doping impurities at various depths. The thin film of non-monocrystalline semiconductor material has at least one tapered region terminating in a point. The thin film of non-monocrystalline semiconductor material is traversed with a particle beam. The traverse is initiated at the point causing nucleation of a crystal at the point and subsequent growth of a monocrystalline thin film of semiconductor material from the point during the traverse. Contacts are then established at various depths to provide a semiconductor device, such as a bipolar transistor.

Thin film semiconductor device and method for manufacture

In the fabrication of Schottky barrier diodes, in conjunction with active devices such as transistors, it has become the conventional practice to use reactive ion etching (RIE) to remove a protective layer of Si.sub.3 N.sub.4. This step of etching is used in forming the anode regions of the Schottky barrier diodes, as well as the active device regions of the transistors. It has been discovered by the present inventors that 'resistive shorts' which have been produced in this context--thus ruining the Schottky barrier function--result from the fact that pinholes in the underlying oxide insulating layer permit the reactant gas to etch all the way down to the silicon substrate so as to produce diffusion paths or 'pipes' through the oxide. Accordingly, instead of the oxide layer acting to block diffusion in the Schottky anode areas, these diffusion paths permit the resistive shorts to be formed. The present invention involves the use of a low energy collimated ion beam in an inert atmosphere, e.g. argon gas, to selectively remove the protective layer. In so doing the ion beam removes the Si.sub.3 N.sub.4 without attacking any of the pinholes in the underlying oxide at the anode areas.

Process for improving the yield of integrated devices including Schottky

A very high current ion implanted emitter is formed in a diffused base. Windows are made through the silicon nitride and silicon dioxide layes to both the base contact and the emitter regions using a resist mask. These regions are then protected by resist and the collector contact window is opened through the remainder of the silicon dioxide layer to the reach through region. A screen oxide is then grown in all the exposed areas after the removal of the resist mask. A resist mask is applied which covers only the base and Schottky anode regions. Arsenic is then implanted through the exposed screened areas followed by an etch back step to remove the top damaged layer. With some remaining screen oxide serving as a cap, the emitter drive-in is done.

Bipolar transistor fabrication process with an ion implanted emitter

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Wappingers Falls, NY, United States of America

Arunachala Nagarajan