Patent GB-975767-A (GB)
Title: Improvements in or relating to the production of semi-conductor arrangements
IPC: H01L21/00
Filed: 1962-06-28
Abstract: <PICT:0975767/C1/1> A semi-conductor arrangement comprising a mono-crystalline semi-conducting body of silicon or germanium and deposited thereon a layer of semi-conducting material of the same lattice structure, but having a different type of conductivity, and/or having a different doping concentration, is produced by stacking a plurality of wafers of semi-conducting material having the same lattice structure so that adjacent wafers have different types of conductivity and/or have different doping concentrations, and forming a temperature gradient along the stack of wafers placed in a reaction zone containing a reaction medium, such as a halide of silicon or germanium, capable of forming a gaseous compound by reaction with the wafers whereby semi-conducting material is transported from one wafer to the next.  As shown, a stack 3 of alternating p- and n-conducting silicon wafers, doped respectively with boron and arsenic and previously lapped and etchpolished, e.g. in a mixture of 40% HF and fuming HNO3, is supported on a silicon support 7 in a quartz tube 2 disposed in an electric resistance furnace 6.  An induction heating coil may be provided. The tube is exhausted and a silicon halide, e.g. SiHCl3 or SiCl4 with hydrogen as a carrier gas is admitted via connection 4, a cock 5 sealing the tube.  The tube is heated to 1200 DEG  C. and then withdrawn from the top of the furnace at a speed of less than 5 mm./min., producing the desired temperature gradient resulting in the transport reaction. The operation may be repeated to increase the thickness of the layer and the wafers may be spaced apart with quartz crystals interposed. Regions on the wafers on which no deposition is desired may be covered with masks, e.g. of mica, graphite, molybdenum or tantalum. Specification 865,160 is referred to.ALSO:<PICT:0975767/C6-C7/1> A semi-conductor arrangement comprising a mono-crystalline semi-conducting body of silicon or germanium and deposited thereon a layer of semi-conducting material of the same lattice structure, but having a different type of conductivity, and/or having a different doping concentration, is produced by stacking a plurality of wafers of semi-conducting material having the same lattice structure so that adjacent wafers have different types of conductivity and/or have different doping concentrations, and forming a temperature gradient along the stack of wafers placed in a reaction zone containing a reaction medium, such as a halide of silicon or germanium, capable of forming a gaseous compound by reaction with the wafers whereby semi-conducting material is transported from one wafer to the next. As shown, a stack 3 of alternating p- and n-conducting silicon wafers, doped respectively with boron and arsenic and previously lapped and etch-polished e.g. in a mixture of 40% HF and fuming HNO3, is supported on a silicon support 7 in a quartz tube 2 disposed in an electric resistance furnace 6.  An induction heating coil may be provided. The tube is exhtausted and a silicon halide e.g. SiHCl3 or SiCl4 with hydrogen as a carrier gas is admitted via connection 4, a cock 5 sealing the tube.  The tube is heated to 1200  DEG C. and then withdrawn from the top of the furnace at a speed of less than 5 mm./minute producing the desired temperature gradient resulting in the transport reaction.  The operation may be repeated to increase the thickness of the layer and the wafers may be spaced apart with quartz crystals interposed.  Regions on the wafers on which no deposition is desired may be covered with masks e.g. of mica, graphite, molybdenum or tantalum. Specification 865,160 is referred to.