Patent GB-1056430-A (GB)
Title: Epitaxial process and apparatus for semiconductors
IPC: C30B25/14
Filed: 1963-11-12
Abstract: In a method of epitanially extending a semi-conductor substrate is heated in a reaction chamber to a temperature that will promote epitanial growth and a gaseous flow of reactants including a compound of the substrate material is directed in laminar flow pattern substantially perpendicularly on to the substrate to cause decomposition of the reactants and growth of the substrate.  Fig.2 shows apparatus for carrying out the process, the apparatus comprising a dome 63 sealed by a sealing ring 62 to a base plate 51 having ducts 52 therethrough for a cooling fluid.  A high purity graphite strip 53, having a reduced middle portion 54 to act as holder for a substrate 70, is mounted on posts 55 through which the graphite strip is connected to a source of electrical power for heating purposes.  A block 67 mounted at the apex of the dome has bores 82 and 69 for conducting reaction gases to inlet funnel 80. The apparatus is exhausted through pipe 73.  Pipe 63 is connected to a helium source for purging.  In the treatment of a germanium substrate the apparatus is purged and the substrate heated to 850 DEG C-900 DEG C. Reaction mixture of germanium tetrachloride and <PICT:1056430/C6-C7/1> hydrogen and dope, which may be phosphine or diborane, is introduced from funnel 80 together with hydrogen chloride as etch gas.  The hydrogen chloride flow is cut off after about one minute and the other reactants are flowed to give a growth rate between ./mil and .25 mil/minute.ALSO:<PICT:1056430/C1/1> In a method of epitaxially extending a semi-conductor substrate such as silicon, the substrate is heated in a reaction chamber to a temperature that will promote epitaxial growth and a gaseous flow of reactants including a compound of the substrate material is directed in laminar flow pattern substantially perpendicularly on to the substrate to cause decomposition of the reactants and growth of the substrate.  Fig. 2 shows apparatus for carrying out the process, the apparatus comprising a dome 63 sealed by a sealing ring 62 to a baseplate 51 having ducts 52 therethrough for a cooling fluid.  A high purity graphite strip 53, having a reduced middle portion 54 to act as holder for a substrate 70, is mounted on posts 55 through which the graphite strip is connected to a source of electrical power for heating purposes.  A block 67 mounted at the apex of the dome has bores 82 and 69 for conducting reaction gases to inlet funnel 80. The apparatus is exhausted through pipe 73.  Pipe 63 is connected to a helium source for purging.  In the treatment of a silicon substrate the apparatus is purged and the substrate heated to 1160-1200 DEG  C. The reaction mixture of trichlorosilane or silicon tetrachloride and hydrogen is introduced together with dopes such as phosphine, arsine, diborane or boron tribromide, the flow rate being such as to provide a growth rate up to 0.25 mil/minute. After the desired thickness is achieved heating is stopped and pure hydrogen is passed into the funnel to cool the substrate to about 100 DEG  C., and then hydrogen is replaced by helium.