Use of germanium doped silicon (n-Si) for manufacturing radiation hardened devices and integrated circuits

We have investigated the possible application of germanium doped CZ silicon, (n-Si) to the manufacture of rad hard bipolar npn transistors, ICs and low power thyristors. The radiation sensitivity of bipolar npn transistors depends on the Ge concentration in the source silicon wafers. The functional failure level of bipolar TTL IC, manufactured using dielectric isolation technology on initial n-Si wafers, doped by germanium up to a concentration of 7.5/spl times/10/sup 19/ cm/sup -3/, may be theoretically eight times greater, than for those, manufactured by the standard technology. For npnp structures, manufactured on n-Si this work showed the radiation hardness improvement of the thyristor holding current.