A bipolar mechanism for alpha-particle-induced soft errors in GaAs integrated circuits

The alpha-particle-induced collected charge in undoped LEC semi-insulating GaAs is measured in n⁺-i-n⁺ and n ⁺-p-n⁺ isolation structures and is compared with the results of an analytical model based on a bipolar mechanism. In n ⁺-i-n⁺ isolation structures, a collected-storage multiplication phenomenon induced by alpha-particle incidence is observed. The measured collected charge is about three times the alpha-particle-generated charge. This phenomenon can be attributed to charge transfer between two adjacent n⁺ regions. The dominant charge-collection process continues for 2.4 ns in n⁺-i-n⁺ isolation structures, but in n⁺-p-n⁺ isolation structures, it stops within 0.8 ns. The measured collected charge decreases as the isolation gap and background acceptor concentration increase. These experimental results can be explained semiquantitatively by the analytical model. This suggests that the primary mechanism of soft errors in GaAs ICs is a bipolar mechanism