Radiation-Hardened Performance-Optimized I2L LSI
Experimental data and theoretical calculations are presented on the effects of neutron irradiation on I2L circuits. It is shown that neutron-induced degradation of I2L gate performance can be theoretically predicted with reasonable accuracy. Operation of custom designed I2L 32-bit serial shift registers to a neutron fluence level of 1 × 1014n/cm2 is demonstrated. Shift register data are also given from total dose gamma and transient upset radiation experiments with thresholds exceeding 3 × 106rads(Si) and 2 × 109rads(Si)/s, respectively.
Recombination dependent characteristics of silicon P+−N−N+ epitaxial diodes
Abstract The low level injection d.c. and transient characteristics of a P+−N−N+ diode are discussed from a theoretical point of view, using the minority carrier lifetime ‘τepi’ in the lightly doped region and the parameter α defining the properties of the high-low junction, as basic parameters. A value of α less than unity is predicted for typical epitaxial silicon structures. Detailed experimental studies involving both lifetime measurements (using optical techniques) on the original epitaxial layer and substrate and d.c. plus transient measurements on completed devices confirm the existence of a ‘blocking’ high low junction (α less than unity). However the measured value of α is still considerably higher than that predicted from the theory, thus indicating conclusively the presence of additional recombination mechanisms at the high low junction interface. An interesting and useful result of the study is the fact that using a combination of d.c. and transient measurement techniques, both α and the effective epitaxial layer width Wepi can be uniquely determined using the given theoretical curves.
Energy
Energy is often defined as the ability to do work. There are many forms of energy. A few examples include; Gravitational energy, Kinetic energy (energy of motion), Thermal energy (heat energy), Potential energy. Potential energy is the energy something has based on its position in the universe. A stretched elastic band has potential energy. A rock held up in the air has potential energy based on its position.