Bell Telephone Laboratories

Thomas E Seidel

Masakazu Shoji

George K Celler

Harry John Leamy

A method of making solid state devices having multilayer dopant distributions, including p-p+ and n-n+ junctions, etc. A semiconductor body is rapidly melted, typically by a laser, electron beam, or ion beam. Present in the melt is a first dopant having a low segregation coefficient and a second dopant having a high segregation coefficient. During rapid resolidification of the melt, the first dopant segregates toward the surface, while the second dopant remains substantially in place, producing a junction. The production of diodes, bipolar and field effect transistors, Schottky barriers, ohmic contacts, junction isolated surface regions, high conductivity paths, etc., is possible by this method.

Formation of multilayer dopant distributions in a semiconductor

The sharp features that appear on metallization patterns defined by conventional etching processes can be eliminated by instantaneous melting with short laser pulses. Flow is minimized due to the brevity of the lifetime of the molten state but surface tension removes the sharp corners. With polysilicon metallization conductivity is also improved.

Metallization for integrated circuits

In semiconductor integrated circuits, piezoresistance is recognized as a factor affecting production yield and circuit performance. Current flow in a circuit resistor is aligned with one of the &lt;100&gt; family of equivalent directions. When current is flowing along such a direction the change in resistance due to any combination of stress components is at a minimum. Additionally, variation of resistance due to stress and strain may be reduced by an increase of the total impurity concentration in a resistor.

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Berkeley Heights, NJ, United States of America

Thomas E Seidel