Patent GB-1069525-A (GB)
Title: Improvements in or relating to methods of manufacturing semiconductor devices
IPC: H01L21/205
Filed: 1964-06-05
Abstract: 1,069,525. Semi-conductor devices. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. June 5, 1964 [June 10, 1963], No. 23410/64. Heading H1K. In a method of producing a semi-conductor device from a semi-conductor body having at least locally a surface layer of silicon oxide, the oxide is removed from a predetermined area of the body and a silicon layer is grown in its place, both steps being performed in the same reaction vessel by leading a gas containing a silicon compound over the heated body so that silicon is liberated at the body. As shown, Fig. 1, an N-type silicon body 9 is enclosed in a reaction vessel 1 and rests on a support 8 which canbe heated by high-frequency coil 12. Hydrogen from cylinder 20 is passed through purifier 22 and is used to flush the reaction vessel. Body 9 is then heated in this gas flow to remove any oxide. Part of the hydrogen flow is then directed through evaporator 28 which introduces a silicon compound, e.g. SiCl 4  or SiHCl 3 , into the gas stream to deposit a layer 13 of silicon, which may be N-type, on the surface of body 9. Carbon dioxide from cylinder 29 is now added to the gas stream to form a layer 14 of silicon oxide on layer 13. The carbon dioxide flow is stopped and a masking member 32, of molybdenum, tungsten, quartz, silicon, or carbon, is lowered on to the wafer by means of ring 34 supported by rod 35. The flow of gas is reduced and the areas of silicon oxide exposed by apertures 33 in mask 32 are removed due to deposition of silicon which combines with the silicon oxide to form silicon monoxide, which is volatile. When the cavities reach the silicon layer 13 silicon is deposited on the exposed surface and grows in thickness without any change in the operating condition. During growth of silicon layers 42 (Fig. 4), which may' be doped with boron, mask 32 may be removed allowing the remaining part of silicon oxide layer 14 to be reduced in thickness. The gas flow through evaporator 28 is stopped and the wafer is heated to diffuse P-type impurity from layer 42 into layer 13 to form junctions 44. The gas flow is then stopped, and the wafer is cooled and divided by scribing and breaking into PNN<SP>+</SP> diodes to which contacts are applied. The masking of the silicon oxide layer may also be performed during its deposition by forming a thin layer of oxide on which is placed a mask which covers the areas where the silicon layers are to be deposited. Deposition of silicon oxide is continued round the mask which is then removed and the thin portions of silicon oxide uncovered are removed by the previously described method and silicon is deposited on the exposed surface of layer 13. The diode structure produced by either method may be covered with an oxide layer and the device precessed as before to produce an N<SP>+</SP> silicon layer on the P-type to form a transistor. The method may be used to produce solid-state circuits containing transistor and/or diode structures. In a further embodiment part of the silicon body exposed by removal of the oxide layer may be removed, e.g. by using hydrogen containing a high concentration of SiCl 4  and/or HCl, and a silicon layer then deposited in the cavity. The original body may be a semi-conductor layer on a metallic or ceramic carrier and the semi-conductor material may also be a III-V compound such as aluminium phosphide. A diagram and numerical values are given for determining the appropriate production parameters.