The hole diffusion length, hole lifetime, hole mobility, and hole equilibrium concentration in epitaxial heavily phosphom-doped silicon have been measured by a combination of steady-state and transient techniques. Steady state measurements were performed on bipolar transistors in which the base was epitaxially grown. The transient measurement relied on the observation of the decay of the photoluminescence radiation after laser excitation. Significant findings are: 1) the hole mobility is about a factor of two larger in heavily doped n-type silicon than in p-type silicon; 2) the apparent bandgap narrowing is smaller than previously thought, with a value of about 90 meV at a doping level of 10'' cm-'.

Artificial neural networks based on crossbar arrays of analog programmable resistors can address the high energy challenge of conventional hardware in artificial intelligence applications. However, state‐of‐the‐art two‐terminal resistive switching devices based on conductive filament formation suffer from high variability and poor controllability. Electrochemical ionic synapses are three‐terminal devices that operate by electrochemical and dynamic insertion/extraction of ions that control the electronic conductivity of a channel in a single solid‐solution phase. They are promising candidates for programmable resistors in crossbar arrays because they have shown uniform and deterministic control of electronic conductivity based on ion doping, with very low energy consumption. Here, the desirable specifications of these programmable resistors are presented. Then, an overview of the current progress of devices based on Li+, O2−, and H+ ions and material systems is provided. Achieving nanosecond speed, low operation voltage (≈1 V), low energy consumption, with complementary metal–oxide–semiconductor compatibility all simultaneously remains a challenge. Toward this goal, a physical model of the device is constructed to provide guidelines for the desired material properties to overcome the remaining challenges. Finally, an outlook is provided, including strategies to advance materials toward the desirable properties and the future opportunities for electrochemical ionic synapses.

Several authors have suggested that a focus on manufacturing capability and on continued process improvement may be a powerful source of competitive advantage, yet many firms appear to have encountered great difficulties in taking advantage of this insight. This paper reports on the results of five these conducted under the auspices of the MIT Leaders for Manufacturing program at the Microwave Technology Division of the Hewlett‐Packard Company. We found considerable evidence that the marginal returns to process development within the division were probably considerably higher than the division's cost of capital, suggesting that process improvement probably was underfunded despite the fact that improving manufacturing capability had been identified as a key strategic priority. We found no evidence that this “underfunding” reflected either a failure to recognize the problem or an overly hierarchical or rigid organization. Rather it appeared to flow from the historical strengths of the division. A devotion to leading‐edge technical solutions and to immediate customer service at almost any price had created barriers to the effective funding of process improvement that were deeply rooted in the organizational structures, information systems, and formal and informal incentive structures that had evolved to support the division's historical emphasis on excellence on product design. Our results highlight the problems that very successful product‐driven companies may encounter in attempting to make continual process improvement central to their strategic mission.

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