Abstract 1,149,215. Transport of III-V compounds. SIEMENS A.G. 4 Aug., 1966 [5 Aug., 1965], No. 34893/66. Heading C1A. In a process for growing an epitaxial layer of a III-V semi-conductor compound by a transport reaction in which the solid compound is converted in a reaction vessel in the presence of a reaction gas into gaseous substances which are conveyed to a point in the vessel at a temperature different from that of the starting material and react to re-form the compound, an additive which reacts with the less volatile of the component elements of the compound to form a non-volatile nitride is added to the reaction gas. The compound may be GaAs, GaP, InAs or InP and may be deposited on a monocrystalline carrier of the same or different material, e.g. GaAs on GaAs or Ge. The additive may be NH 3 gas (which forms GaN with Ga) and may be produced by vaporizing aqueous ammonia solution or liquid NH 3 , or by decomposing solid ammonium carbamate. The reaction gas may be a mixture of H 2 O and H 2 in the mole ratio 0À1-0À3. The transport may be effected by passing the reaction gas first over the powdered compound and then over the carrier (as in Fig. 1) or by using immediately adjacent compound and carrier, e.g. by arranging a carrier plate above the powdered or tabletted compound and separating them with an annular spacer (as in Fig. 2). A doping agent may be added to the starting material or to the reaction gas, or may be placed separately in the vessel.
IN THE METHOD OF GROWING EPITAXIAL LAYERS OF STOICHIOMETRICALLY COMPOSED SEMICONDUCTOR COMPOUNDS, WHOSE COMPONENTS HAVE RESPECTIVELY DIFFERENT VAPOR PRESSURES, BY A CHEMICAL TRANSPORT REACTION COMPRISING THE STEPS OF SUBJECTING SOLID SEMICONDUCTOR SOURCE MATERIAL AT ONE LOCALITY IN A REACTION VESSEL TO A REACTION GAS FOR CONVERTING THE SOURCE MATERIAL TO THE GASEOUS STATE AND TRANSPORTING IT WITH THE REACTION GAS TO A SUBSTRATE SITUATED AT A DIFFERENT VESSEL LOCALITY HEATED TO A TEMPERATURE DIFFERENT FROM THAT OF SAID ONE LOCALITY SO AS TO PRECIPITATE THE SEMICONDUCTOR COMPOUND UPON THE SUBSTRATE, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE REACTION GAS AMMONIA WHICH FORMS A NON-VOLATILE COMPOUND WITH THE LESS VOLATILE ONE OF THE COMPONENTS OF SAID SEMICONDUCTOR COMPOUND. WHEREBY SAID ADDED SUBSTANCE BINDS THE EXCESS AMOUNT OF SAID ONE COPONENT EVOLVING, DUE TO THE DIFFERENCE IN VAPOR PRESSURES, FROM THE TRANSPORT REACTION.
Claim 2
Dependent Claim
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IN THE METHOD OF GROWING EPITAXIAL LAYERS OF STOICHIOMETRICALLY COMPOSED SEMICONDUCTOR COMPOUNDS, WHOSE COMPONENTS HAVE RESPECTIVELY DIFFERENT VAPOR PRESSURES, BY A CHEMICAL TRANSPORT REACTION COMPRISING THE STEPS OF SUBJECTING SOLID SEMICONDUCTOR SOURCE MATERIAL AT ONE LOCALITY IN A REACTION VESSEL TO A REACTION GAS FOR CONVERTING THE SOURCE MATERIAL TO THE GASEOUS STATE AND TRANSPORTING IT WITH THE REACTION GAS TO A SUBSTRATE SITUATED AT A DIFFERENT VESSEL LOCALITY HEATED TO A TEMPERATURE DIFFERENT FROM THAT OF SAID ONE LOCALITY SO AS TO PRECIPITATE THE SEMICONDUCTOR COMPOUND UPON THE SUBSTRATE, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE REACTION GAS AMMONIA WHICH FORMS A NON-VOLATILE COMPOUND WITH THE LESS VOLATILE ONE OF THE COMPONENTS OF SAID SEMICONDUCTOR COMPOUND. WHEREBY SAID ADDED SUBSTANCE BINDS THE EXCESS AMOUNT OF SAID ONE COPONENT EVOLVING, DUE TO THE DIFFERENCE IN VAPOR PRESSURES, FROM THE TRANSPORT REACTION.