Abstract: Anhydrous ammonium fluoride is used as a safe source of hydrogen fluoride for etching native or other silicon dioxide layers from silicon substrates. Heating the anhydrous ammonium fluoride above its sublimation temperature results in the generation of hydrogen fluoride gas which etches the silicon dioxide. Controlled amounts of water vapor are used during the etch reaction to ensure complete etching of the thin oxide layers down to within hundredths of a monolayer and to achieve precise etch rate control.

Abstract: A method of manufacturing a bipolar transistor by use of low temperature emitter process is disclosed. After completion of the usual base and collector formation in a vertical bipolar transistor, an emitter opening is etched in the insulator layer over the base layer at selected locations. A thin layer (less than 500 .ANG.) of in-situ doped amorphous silicon is deposited over the substrate and heated to densify for 30 to 60 minutes at about 650.degree. C. Subsequently an in-situ doped polysilicon layer of 100 to 200 nm is deposited over the amorphous Si film preferably at about 600.degree. C. Subsequently the layers are heated below 600.degree. C. for several hours to convert partially the amorphous Si into a monocrystalline emitter layer over the base regions.

Abstract: A method of providing sublayer contacts in vertical walled trenches is proposed. In accordance with the present invention, the phosphorus doped amorphous silicon is deposited at temperatures less than 570.degree. C. The conversion into the extremely large crystal low resistivity polysilicon is accomplished by a low temperature anneal at 400.degree. C. to 500.degree. C. for several hours and a short rapid thermal anneal (RTA) treatment at a high temperature approximately 850.degree. C. for twenty seconds. These two conversion heat treatments are done at sufficiently low thermal budget to prevent any significant dopant movement within a shallow junction transistor. After anneal, the excess low resistivity silicon is planarized away by known techniques such as chemical/mechanical polishing.

Abstract: An injector with a convex wall surface facing the susceptor directs vapor toward a wafer held by a susceptor producing a generally laminar flow across the surface of the wafer that in combination with the convex wall surface prevents formation of recirculation cells in the region between the wafer and the injector.