Bell Telephone Laboratories

Western Electric Company, Inc.

James T Clemens

Charles Walter Pearce

Frank J Procyk

John D Cuthbert

James T Nelson

Kay M Locke

Robert C Sun

George M Trout

Dinesh A Mehta

A contact structure and method of fabrication for achieving shallow junction MOS integrated circuits. An insulator (23) such as phosphosilicate glass is deposited over the circuit and contact windows (24 and 25) opened therein. Fire polishing of the glass is eliminated so that the junctions can be made shallow and the sides of the windows remain steep. A layer of polycrystalline silicon (26) is deposited over the insulator and the contact windows so as to conformally coat the sides of the windows and the exposed semiconductor. A contact metal (28 and 29), such as aluminum, is deposited over the polycrystalline silicon. The metal tends to be essentially discontinuous over the steep sides of the windows, but the polycrystalline silicon layer has sufficiently low resistivity to provide adequate conduction in these areas.

Structure for shallow junction MOS circuits

A memory in which each cell comprises an MOS transistor merged with a storage capacitor and in which the cells are arranged to permit adjacent pairs of transistors in a common column to share a common source and the transistors in a common row to share a common gate electrode conductor. The memory uses a first polycrystalline silicon layer which is patterned to provide interconnected storage electrodes and a second polycrystalline silicon layer which is patterned to provide a plurality of stripes to serve as the bit sense lines and a plurality of gate electrodes.

Dynamic random access memory

In a dynamic MOS (Metal Oxide Semiconductor) random access memory, reverse bias leakage currents which deplete stored charges are reduced by minimizing minority carrier generation-type currents. By so minimizing these currents, the leakage currents become dominated by minority carrier diffusion currents. The memory is ideally formed in an upper semiconductor layer (14) of a layered structure (11). The semiconductor layer (14) is grown epitaxially with a relatively low dopant concentration on a semiconductor substrate (12) with a dopant concentration of the same conductivity type and about three orders of magnitude greater than that of the epitaxially grown layer. The epitaxially grown structure is advantageously suited for the memory circuits in that it may be formed with very low leakage currents. The material further offers by its layered structure a basis for optimizing dynamic memory device characteristics.

MOS Dynamic memory in a diffusion current limited semiconductor structure

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Allentown, PA, United States of America

James T Clemens