Ionization effects of the heavy components of cosmic radiation in protected chips

Radiation effects leading to degradation and failures in the operation of electronic equipment on board a space ship are of increasing concern in connection with the constantly decreasing sizes and increasing density of modern onboard microelectronics elements. The propagation of the energetic heavy ions of galactic cosmic rays (GCR) through a multi-layer structure (an integrated-circuit prototype) is discussed in the paper. The amount of electron-hole pairs induced by an ion in the sensitive area of a transistor has been estimated with consideration for energy losses in the chip body as well as in the protective oxide layers, contacts, and metallized layers. Calculation of the energy of various particles initiating the generation of a charge potentially capable to induce a single failure of onboard electronics has been carried out. The existence of a spatial region from which heavy fragments of a nuclear reaction, with a kinetic energy sufficient enough to induce a charge above the critical one, can penetrate into the gate region of a transistor has been demonstrated.