| 摘要 |
1376973 Epitaxial substrate growth PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 9 May 1972 [12 May 1971] 21537/72 Heading BIS [Also in Division H1] A plate comprising a monocrystalline substrate of gallium arsenide on which, by liquid epitaxy, has been grown a monocrystalline semiconductor material consisting mainly of arsenic, gallium and aluminium is made by providing a saturated homogeneous solution of arsenic in a melt of gallium and aluminium in a crucible then contacting the solution at a temperature of (TŒ3)‹C with the substrate and then cooling the solution in contact with the substrate. The temperature T‹C is defined by the equation: T=844+[(3200 log 10 (C L +0.7)]<SP>0.7575</SP> where C L which lies between 0.05 and 0.8%, is the percentage by weight of aluminium in the solution calculated with respect to the weight of gallium in the melt which is in excess of the stoichiometric composition of gallium arsenide. If desired an n-type semiconductor material may be obtained by carrying out the liquid epitaxy in the presence of a flow of hydrogen which contains tellurium. The growth is effected by placing in a furnace 1, crucible 2, which is separated into two parts 3 and 8 by horizontally movable partition 5 via slots 6. As shown, 4 is the gallium arsenide substrate and 9 the mixture of the layer materials. The assembly is heated to the chosen temperature T‹C until a homogeneous solution of the materials is achieved, after which partition 5 is withdrawn and solution 9 then contacts substrate 4, and the crucible slowly cooled, e.g. by 200‹C. The coated substrate is subsequently withdrawn from the furnace and residual liquid gallium removed. |
