Repairing phosphorus-doped silicon monocrystal lattice defects - by heating to temper crystal at temp. dependent on neutron irradiation conditions

摘要

Crystal lattice defects are repaired in silicon monocrystals by tempering, where the Si has been doped with the phosphorous isotope 31P by neutron irradiation. The Si is heated for =30 minutes at a min. temp. (T1) which depends on the irradication conditions, viz. the ratio(R) of thermal neutrons: fast neutrons, and on the carbon content in the Si. Where R is 100:1 or 99% thermal neutrons, T1 is pref. 700 degrees C. irrespective of the %C. Where R is between 1:1 and 10:1, T1 is 1100 degrees C. for a C content of 3 x 1016 atoms/cm3, and 750-1000 degrees C. for C content 3 x 1016 atoms/cm3. For r between 10:1 and 100:1, T1 is 1000 degrees C. for a C content 3 x 1016 atoms/cm3, and 750 degrees C for a C content 3 x 1016 atoms/cm3. The tempering treatment is pref. independent of the furnace atmos. Used e.g. in the mfr. of semiconductor elements and devices. Stable electrical properties are obtd.