The semiconductor community is developing three-dimensional circuits that integrate logic, memory, optoelectronic and radio-frequency devices, and microelectromechanical systems. These three-dimensional (3D) circuits pose important challenges for thermal management due to the increasing heat load per unit surface area. This paper theoretically studies 3D circuit cooling by means of an integrated microchannel network. Predictions are based on thermal models solving one-dimensional conservation equations for boiling convection along microchannels, and are consistent with past data obtained from straight channels. The model is combined within a thermal resistance network to predict temperature distributions in logic and memory. The calculations indicate that a layer of integrated microchannel cooling can remove heat densities up to 135W/cm2 within a 3D architecture with a maximum circuit temperature of 85°C. The cooling strategy described in this paper will enable 3D circuits to include greater numbers of active levels while exposing external surface area for functional signal transmission.

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We report on the fabrication of organic light-emitting devices (OLEDs) using a thin NaCl interlayer as an electron-injection medium. The results show that the device containing the NaCl layer has a higher brightness and electroluminescent efficiency than the device without this layer. We also fabricated similar-structured comparable devices, which were prepared with a LiF layer as a different electron-injection medium. The maximum electroluminescent efficiency of the NaCl (1 nm)/Al cathode device was 2.85 cd/A, which is higher than the 2.25 cd/A of the LiF (1 nm)/Al cathode device. The ultrathin NaCl layer modified the carrier injection properties. In conclusion, the NaCl layer between a cathode and an emitting layer of OLEDs can be used as the carrier injection layer to improve the EL properties.