GB1388286A - Monocrystalline materials - Google Patents

Abstract

1388286 Crystal pulling SIEMENS AG 26 May 1972 [28 May 1971] 25097/72 Heading BIS In the production of a monocrystal by the method of Czochralski, the material to be pulled by a seed crystal is in part introduced into the crucible in particulate form and fused therein and then the remainder is lowered into the crucible and also fused therein. A layer of protective material e.g. boron oxide is preferably fused on top of the material from which the monocrystal is pulled. The remainder of the material is preferably supplied in the form of a rod which is attached to the seed crystal and lowered into the fused particulate material. After fusion of the rod and attainment of equilibrium in the crucible the seed crystal is dipped into the fused material and the crystal pulled therefrom. The material is preferably a semiconductor such as gallium phosphide, nitride, arsenide, or antimonide, indium arsenide, phosphide or antimonide, or aluminium arsenide or antimonide. The figure shows a preferred method of carrying out the process. In pulling chamber 1, is disposed, between H.F. coil 5 and quartz chamber 6, crucible 2 contained in a graphite suseptor 3, and surrounded by a felt 4. The crucible has an intermediate bottom 22 and is positioned on a stand 9 which is rotatable and moveable vertically by shaft 10. Reference numeral 11, designates the surface of the particulate material and 12 that of the boron oxide layer. Numeral 13 indicates the surface of the fused particulate material. The additional added material is in the form of a rod 14 suspended by dovetail connection 16 from seed crystal 15, and via link rod 17 is lowered into the crucible to give a surface 18 of fused material from which the monocrystal is drawn. Numerals 19 designate viewing tubes.