A 7000-gate microprocessor on SOS&#8212;PULCE
An n-channel MOS LSI microprocessor integrating 20 000 transistors on a chip has been realized on a sapphire substrate utilizing the Coplanar-II process. It contains ALU, shifters, and 44 registers which are combined to three 16-bit buses. By utilizing three types of threshold voltage for load transistors, 28-percent reduction in power dissipation is achieved. The minimum cycle time is 200 ns. By using the Coplanar-II process, anomalous leakage currents due to parasitic transistors at the sides of island are suppressed. It is found that the silicon-on-sapphire (SOS) version operates 2.3 times faster than the bulk-silicon version, which is mainly explained by the parasitic capacitance ratio. Parallel-plate approximation in calculating a wiring capacitance results in an underestimate by a factor of 60 compared with taking the two-dimensional effect into account. It is verified that a) the observed yield of a very large SOS chip is higher than the value predicted from a randomly distributed defects model, and b) the yield-sensitive active area of an SOS is so small that it can compensate for the yield degradation due to the very large defects density on an SOS wafer.
A comparison of fine-dimension silicon-on-sapphire and bulk-silicon complementary MOS devices and circuits
The fabrication of fine-dimension silicon-gate MOS devices on both silicon-on-sapphire and bulk-silicon substrates has made possible a direct comparison of the electrical characteristics of devices based on these technologies. The same CMOS test chip design was used in both cases and provided both n- and p-channel devices having gate dimensions ranging down to submicrometer levels. Extensive electrical evaluation of the resulting devices has enabled quantitative comparison of carrier mobilities, short- and narrow-channel threshold voltage shifts, punchthrough, and subthreshold characteristics for SOS and bulk-silicon technologies. The effect of epitaxial film thickness on these properties for SOS devices is also discussed. An anomalous narrow-channel threshold voltage shift effect is observed in SOS devices and explained in terms of parasitic device characteristics. The general conclusion based on the observations made is that short-and narow-channel effects in SOS devices are significantly less of a problem than in bulk silicon devices at these gate dimensions. The direct comparison of the dynamic performance of SOS and bulk CMOS circuits can be obscured, for example by differences in gate oxide thickness and threshold voltages. In this case, however, both gate oxide thickness and threshold voltages have been closely matched. This, together with the fact that the circuits were fabricated by the same processing facility using the same chip design, should increase the reliability of any comparison. The results have indicated that at 1-µm dimensions the propagation delay of SOS CMOS circuits is 60 percent lower than that of equivalent bulk-silicon CMOS circuits.
Understanding the broader implications of strategic evidence disclosure in police interviews with suspects
Police around the world present evidence to suspects at different points during the interview. Some psychologists suggest that police should strategically delay disclosing evidence and test the truthfulness of a suspect’s account by comparing it with the evidence. Moreover, psychologists suggest interviewers who plan strategic evidence disclosure might be less guilt-presumptive about the suspect because they must consider alternative explanations of the evidence as part of their planning. In contrast, many lawyers argue that police should not strategically disclose evidence as it undermines a suspect’s fair trial rights and prevents lawyers from advising suspects effectively before the interview. 
 
To address these conflicting perspectives from the domains of psychology and law, this thesis takes an interdisciplinary approach and considers strategic evidence disclosure within the broader legal context of a suspect’s custodial detention. First, a field study of police disclosure briefings with lawyers, lawyer-client consultations, and police interviews, and a survey of lawyers highlights how lawyers rely upon the police’s evidence to advise suspects in custody. When police strategically disclose evidence, lawyers cannot provide informed legal advice and tend to advise suspects to not answer police questions. Second, three experiments and a mini meta-analysis show that generating alternative evidential explanations for criminal cases, as interviewers planning strategic evidence disclosure might do, has a very small effect, or plausibly no effect, on people’s beliefs about the suspect’s guilt. Finally, a mock crime experiment shows that, even two months after a crime, truthful suspects’ accounts fit evidence that was strategically withheld more than deceptive suspects’ accounts did. Independent laypeople from a follow-up experiment could distinguish between these truthful and deceptive accounts. Together, these findings suggest that strategic evidence disclosure could help deception detection even months after a crime, but it also impinges upon suspects’ legal rights and is unlikely to make interviewers less guilt-presumptive.