Reliability of MINP compared to MIS, SIS, and N/P silicon solar cells under 1.0-MeV electron and environmental effects

The effects of 1.0-MeV electron radiation are compared for MIS, SIS, N/P, and MINP silicon solar cells. MIS, SIS, and N/P silicon solar cells are comparable in performance except that SIS cells degraded faster due to use of n-type Si substrates. MINP cells exhibited superior performance in that efficiency degraded 9 percent at a fluence of 1 × 10
¹⁵
e
^-
/cm
²
and 32 percent at a fluence of 1 × 10
¹⁶
e
^-
/cm
²
compared to 29 percent and 49 percent, respectively, for N/P cells. MINP cells utilize an SiO
2
insulator layer over a thin N-region, and a low work function metal contact. This design gives a high ultraviolet response and low surface recombination velocity which maintains high efficiency since most of the radiation loss occurs in the infrared region due to bulk damage effects.