Radiation testing of the CMOS 8085 microprocessor family

Radiation testing of the SA3000 family, CMOS versions of the Intel 8085 microprocessor family, has demonstrated full functionality after 3 x 106 rad (Si) total dose. Static supply currents measured after reset increased from approximately 50 etaA to 500 μA at V/sub DD/ = 10V while maximum operating frequency decreased from greater than 10 MHz to 4 MHz at V/sub DD/ = 9V post 3 x 106 rad (Si). Output drive currents decreased 25% post 1 x 106 rad (Si) and 40% post 3 x 106 rad (Si). The nominal threshold voltage shift of discrete transistors measured under worst-case bias (n-channels, ON; p-channels, OFF) shifted -0.5 volts and -2.40 volts post 1 x 106 rad (Si) for n-channel and p-channel MOSFETs, respectively. Transient radiation upset levels of about 1 x 109 rad (Si)/sec have been measured for parts from this family. Latch-up immunity has been demonstrated up to 1 x 1012 rad (Si)/sec and electrical bench tests are discussed which prove this technology is immune to latch-up. The technology used for the SA3000 family is a 3μm silicon gate process fabricated in n and n+ epitaxial silicon. Functional test programs for each chip of the family are discussed