Patent GB-737950-A (GB)
Title: Improvements in and relating to plastic working of semiconductors
IPC: C30B1/00
Filed: 1953-06-25
Abstract: Germanium or silicon are plastically worked by applying a deforming force to the silicon or germanium while it is maintained at a temperature of between 65 and 85 per cent of its absolute temperature scale melting point.  The invention enables special shapes to be achieved for semiconductor devices.  Germanium is described as becoming deformable at 500 DEG  C. when subjected to a force of between 100 and 3000 pounds per square inch for several minutes, and as being easily deformable without fracture at temperatures above 627 DEG  C. with a force of between 50 and 15,000 lbs./sq. inch.  The material retains its new shape after cooling. Problems of oxidation and introduction of impurities make the use of temperatures above 760 DEG  C. undesirable.  Silicon similarly becomes deformable at about 830 DEG  C., and is readily deformable at 1165 DEG  C. but requires stresses approximately twice those for germanium to effect the same deformation.  The plastic deformation tends to increase the resistivity of the material, and this can be restored to a desired value by annealing the material before or after cooling, following the plastic treatment.  Slip lines, which may appear in the deformed specimen may be removed by etching.ALSO:Germanium or silicon are plastically worked by applying a deforming force to the material while it is maintained at a temperature of between 65 and 85 per cent of its absolute temperature scale melting-point.  The invention enables special shapes to be achieved for semi-conductor as devices. Germanium is described as becoming deformable at 500 DEG  C. when subjected to a force of between 100 and 3000 pounds per square inch for several minutes, and as being easily deformable without fracture at temperatures above 627 DEG  C. with a force of between 50 and 15,000 lbs./sq. inch.  The material retains its new shape after cooling. Problems of oxidation and introduction of impurities make the use of temperatures above 760 DEG  C. undesirable.  Silicon similarly becomes deformable at about 830 DEG  C., and is readily deformable at 1165 DEG  C. but requires stresses approximately twice those for germanium to effect the same deformation.  The plastic deformation tends to increase the resistivity of the material, and this can be restored to a desired value by annealing the material before or after cooling, following the plastic treatment. Germanium may be annealed at a temperature of about 500 DEG  C. for 12 or 24 hours.  Slip lines, which may appear in the deformed specimen, may be removed by etching.ALSO:Germanium or silicon are plastically worked by applying a deforming force to the material while it is maintained at a temperature of between 65 per cent and 85 per cent of its absolute temperature scale melting point.  The invention enables special shapes to be achieved for semi-conductor devices.  Germanium is described as becoming deformable at 500 DEG C. when subjected to a force of between 100 and 3000 pounds per square inch for several minutes, and as being easily deformable without fracture at temperatures above 627 DEG C. with a force of between 50 and 15000 pounds per square inch.  The material retains its new shape after cooling.  Problems of oxidation and introduction of impurities make the use of temperatures above 760 DEG C. undesirable. Silicon similarly becomes deformable at about 830 DEG C., and is readily deformable at 1165 DEG C., but requires stresses approximately twice those for germanium to effect the same deformation.  The plastic deformation tends to increase the resistivity of the material, and this can be restored to a desired value by annealing the material before or after cooling, following the plastic treatment.  Germanium may be annealed at a temperature of about 500 DEG C. for 12 or 24 hours.  Slip lines, which may appear in the deformed specimen may be removed by etching.