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.
Analytical Investigation of Neutron Hardening of Integrated Injection Logic
An analytical technique is presented for investigating the neutron induced degradation of integrated injection logic (I2L) inverter cells as a function of basic processing variables. The technique combines a one-dimensional semiconductor device code, the PN code, with the circuit analysis code SPICE. Predictions of neutron induced degradation as a function of npn transistor base doping, epitaxial thickness and resistivity and pnp transistor base width are presented for a second generation I2L technology. A comparison of predicted response to experimental data is given for inverter cells fabricated with different npn base doping and epitaxial thickness.
Detailed investigation of lateral transistor characteristics
The dc characteristics of the lateral transistor have been studied in detail theoretically and experimemally. Base and collector currents were examined separately as functions of emitter-base bias. In this way, it was possible to obtain a clear understanding of the independence of current gain on factors such as geometry, high-level injection, carrier lifetimes, surface recombination, and emitter efficiency. By independently measuring the relevant physical parameters and inserting their values into the theoretical model, transistor characteristics were obtained which agreed closely with experiment.