Preparation of hot-pressed silicon-germanium ingots: Part III - vacuum hot pressing

Vacuum hot pressing silicon-germanium powders containing 80 atomic percent silicon and sufficient phosphorus or boron to give a carrier concentration of 2 × 1019cc for one hour at 1295°C and 28,000 psi produces ingots of uniform composition with densities of 2.975 to 3.006 g/cm3. Variations in resistivity across and between faces of individual ingots and between ingots are less than about ±5%. Variations in composition on a micron scale are normally less than ±2 atomic percent. Porosity is very low and ultimate strength is on the order of 24,000 psi.