Abstract: A method of manufacturing a semiconductor device in which a thin buried silicide layer is formed by implantation includes the step of first forming an amorphous layer by implantation, which layer is then converted into the buried silicide layer by a heat treatment. A sufficiently thin buried silicide layer, of about 10 nm thickness, can be obtained in this manner, and the resulting structure is suitable, for example, for the manufacture of a metal-base transistor.

Abstract: The invention relates to a method of manufacturing a semiconductor device comprising a semiconductor body (1) having a buried insulating layer (7). Such a type of semiconductor device is known as a device of the SOI type. According to the invention, the starting material is a substrate (1) of monocrystalline semiconductor material with a top layer (2). Ions are implanted into a zone located under the top layer so that the zone becomes selectively etchable with respect to the remaining part of the substrate. The zone is then etched away, a cavity then being formed between the top layer (2) and the remaining part of the substrate (1). The cavity is filled at least in part with insulating material (7). By known techniques, semiconductor circuit elements can be provided in the top layer (2) thus disposed on the insulating layer (7).

Abstract: A method of simultaneously manufacturing semiconductor regions having different doping concentrations, for example, for obtaining semiconductor resistors having differences values. Due to difference in the rate of oxidation, oxide edges of different widths can be formed by oxidation of n-type silicon regions thus obtained. According to the invention, ion implantation or deposition takes place through doping windows for each of which the ratio between the window surface area and the surface area to be doped is different. Subsequently, homogeneous doping concentrations are obtained by diffusion.

Abstract: In a method of manufacturing a semiconductor device, ions are implanted into a layer of silicon nitride over a part of its surface, and the layer is then subjected to an etching treatment. According to the present invention, before the etching treatment takes place, but after the ion implantation, the layer is subjected to a heat treatment in which the implanted part of the layer obtains a higher resistance to etching than the non-implanted part. The heat treatment occurs at temperatures above 750.degree. C. Thus, a negative image of a patterned ion irradiation can be formed in the silicon nitride layer. As a result, the number of cases in which an etching or oxidation mask can be formed in a silicon nitride layer without using additional mask is considerably increased.