Verfahren zum Herstellen einer Halbleiteranordnung

摘要

923,801. Coating with metals; coating by vapour dep sition. SIEMENS & HALSKE A.G. June 13, 1961 [June 13, 1960], No. 21279/61. Class 82. [Also in Group XXXVI] A PN junction is made by deposition of semi-conductor material on a substrate in two stages from a gaseous mixture containing a decomposable compound of the semi-conductor and, in the first stage a donor (acceptor) impurity to form an N(P) layer, and in the second stage an acceptor (donor) impurity to form a P(N) layer. The layers are each less than 500Š thick and the impurities and the temperature of the substrate and rate of deposition in the second stage are so selected that the density of the minority impurity at the side of each region remove from the PN junction resulting from interfacial diffusion is not more than half the density of the same impurity in the other region. A tunnel diode is made in the apparatus shown in Fig. 1 using a monocrystalline silicon substrate 1 on a monocrystalline semi-conductor support 4. The wafer 1 is etch polished and then purified in the chamber by evaporation or surface blasting in a protective gas such as hydrogen or in vacuo. In the first deposition stage silico-chloroform or silicon tetrachloride and hydrogen are introduced into the chamber with a decomposable compound of a donor and a degenerate N type zone 500 Š thick deposited with the substrate at 1100‹ C. In the next stage with the substrate at 1000‹ C. a second more lightly doped (5 Î 1019 donors/c.c.) but degenerate N zone 100 Š thick is formed, the deposition rate being controlled at a low value by addition of an inhibitor such as hydrogenchloride or a diluent such as hydrogen to the gaseous mixture. In this step the donor is obtained by suddenly heating coil 11 containing donor impurity. In a third stage a similarly doped P-type zone 100 Š thick is deposited including acceptor material obtained by suddenly heating coil 12 containing it. The doping materials such as BrP are therefore vapour deposited from heaters 11 and 12. The substrate is maintained at 1000‹ C. during this stage and the deposition rate is rapid. As a result, diffusion between the second and third layers is minimized. Subsequently, a fourth more heavily doped P zone 2000 Š thick is deposited with the substrate at 950‹ C., the deposition rate being maintained at the maximum consistent with obtaining monocrystalline material by removal of inhibitor and diluent gases. A rapid flow of the gas, which is preferably preheated, is maintained throughout the process, the inpurities being thoroughly mixed with the gases by the turbulent flow through vanes 10. If the silicon substrate is replaced by one of metal this forms one electrode of the device, a second being then formed on the fourth zone by deposition from a decomposable metal compound. Use of silane or germane in the above process permits the use of lower substrate temperatures with a consequent reduction in diffusion. Metals may also be deposited by vapour deposition to form required contacts.