Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

The British Petroleum Company, P.l.c.

Walter E Spear

Alan E Owen

Peter G Lecomber

Siegfried Kalbitzer

Gerhard Muller

Peter G Le Comber

Gerard Sarrabayrouse

A semiconductor device comprising superimposed layers of p- and n-doped semiconducting material (e.g. silicon) and electrical contact means for applying an electrical potential across the superimposed layers is characterized in that the p- and n-doped layers are both of amorphous semiconducting mateial (e.g. silicon) and one of said layers is much more heavily doped than the other. Suitably the less heavily doped layer has a thickness which is not greater than 2 .mu.m and the dopant concentration in the more heavily doped layer is one hundred or more times the dopant concentration of the less heavily doped layer. Preferably a third or quasi-intrinsic layer or substantially undoped amorphous semiconducting material (e.g. silicon) or electrically insulating material is applied to one of the doped layers between that layer and its electrical contact means. The device can be used as an electrically-programmable non-volatile semiconductor memory device.

Non-volatile amorphous semiconductor memory device utilizing a forming

To provide for effective doping and obtain substantial conductivity change in amorphous semiconductor material, typically silicon, a body of said material is raised to a temperature above about 20.degree. C. and below the recrystallization temperature, for example in the range of between 100.degree. C., preferably above 200.degree.-250.degree. C. and below about 450.degree. C. during the ion implantation. The doping ions are, for example for silicon, of groups III and V of the periodic system, particularly boron and phosphorus. Semiconductor junctions can be made by this process by selectively doping spatially limited regions of the semiconductor body to thereby produce semiconductor components by doping with ions of different characteristics, for example of different conductivity type.

Method of doping a body of amorphous semiconductor material by ion

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Dundee, United Kingdom

Walter E Spear