Patent GB-963799-A (GB)
Title: Method of epitaxially growing semiconductor material
IPC: H01L21/20
Filed: 1962-12-28
Abstract: <PICT:0963799/C1/1> A semi-conductor is epitaxially deposited from the halide vapour phase on to selected areas of a substrate which is heated to a temperature below the thermal reaction temperature for epitaxial growth, by focusing electromagnetic radiation on to the selected areas to increase the activation energy sufficient for epitaxial growth to take place.  The process is applicable to the deposition of germanium, silicon, compounds of Group III and Group V such as gallium arsenide, indium phosphide and aluminium antimonide and also p-type deposits such as boron and N-type deposits such as arsenic. As shown in Fig. 1 a germanium substrate 17 is placed on a quartz jig 16 in a reaction chamber 10 and positioned adjacent to a window 11. An optical system comprising light source 18 and light filter 20 for passing ultra-violet light, a condensing lens system 19, a mask 21 and a focusing lens system 22 focuses the apertures in the mask 21 on to the substrate 17 which is first heated to 700 DEG C. in a hydrogen atmosphere to reduce oxides and then reduced to 450 DEG  C., i.e. 50 DEG  C. below the reduction temperature of GeCl4. Hydrogen is introduced into the chamber via valve 24, GeCl4 via valve 25 and 1% of AsCl3 via valve 28.  The substrate is activated in selected areas by the optical system and the epitaxial deposit 31, 32 formed.  A neutral gas such as argon or helium may also be introduced into the chamber via valve 24.  After the required thickness of N-type germanium is formed, the process is repeated with the same or a different mask and BCl3 is introduced to deposit P-type germanium. Several layers and different patterns may be produced (Fig. 2, not shown), and a final passivating film may be formed by forming an oxide film from an atmosph ere of O2 or H2O plus GeCl4 or SiO may be produced by the decomposition of silanes.ALSO:A semi-conductor is epitaxially deposited from the halide vapour phase on to selected areas of a substrate which is heated to a temperature below the thermal reaction temperature for epitaxial growth, by focusing electromagnetic radiation on to the selected areas to increase the activation energy sufficient for epitaxial growth to take place.  The process is applicable to the deposition of germanium, silicon, compounds of Group III and Group V such as gallium arsenide, indium phosphide and aluminium antimonide and also P type dopants such as boron and N-type dopants such as arsenic.  As shown in Fig. 1, a germanium substrate 17 is placed on a quartz jig 16 in a reaction chamber 10 and positioned adjacent a window 11.  An optical system comprising light source 18 and light filter 20 for passing ultra-violet light, a condensing lens system 19, a mask 21 and a focusing lens system 22 focuses the apertures in the mask 21 on to the substrate 17 which is first heated to 700  DEG C. in a hydrogen atmosphere to reduce oxides and then reduced to 450  DEG C., i.e. 50 DEG C. below the reduction temperature of GeCl4. Hydrogen is introduced into the chamber via valve 24, GeCl4 via valve 25 and 1% of AsCl3 via valve 28.  The substrate is activated in selected areas by the optical system and the epitaxial deposit 31, 32 is formed.  A neutral gas such as argon or helium may also be introduced into the chamber via valve 24.  After the required <PICT:0963799/C6-C7/1> thickness of N type germanium is formed, the process is repeated with the same or a different mask and BCl3 is introduced to deposit P type germanium.  Several layers and different patterns may be produced, see Fig. 2 (not shown), and a final passivating film may be formed by forming an oxide film from an atmosphere of O2 or H2O plus GeCl4 or SiO may be produced by the decomposition of silanes.