Application of micro-heat pipes for the thermal control of semiconductor devices

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaf 29).Electronic components produce heat that hinders their performance and reliability. Heat pipes, two-phase heat transfer devices, may be used to effectively cool electronic components. This project focuses on two different heat pipe designs that may potentially be used to cool electronic components. One heat pipe design being studied uses metal wires to form its wicking structure. This simple wick design may result in reduced manufacturing costs. The second heat pipe design has a wick pattern formed in a copper plate. The wick pattern is designed to separate the flow of vapor and liquid within the heat pipe. To evaluate both heat pipe designs, test articles were fabricated and tested to determine their heat transfer performance. Tests performed in this study indicated that both heat pipe designs offered no performance benefits when compared to comparable solid conductors. Errors in the charging process and use of improper amounts of working fluid are believed to cause the negligible performance gains

Low effective surface recombination in In(Ga)As/GaAs quantum dot diodes

Size dependent current-voltage measurements were performed on InGaAs quantum dot active region mesa diodes and the surface recombination velocity was extracted from current density versus perimeter/area plots using a diffusion model. An effective surface recombination value of 5.5 x 10(4) cm/s was obtained that can be reduced by more than an order of magnitude by selective oxidation of Al(0.9)Ga(0.1)As cladding layers. The values are three times smaller than those obtained for a single quantum well. The effect of p-type doping in the active region was investigated and found to increase the effective surface recombination. (C) 2011 American Institute of Physics. [doi:10.1063/1.3611387

Fast wavelength switching lasers using two-section slotted Fabry-Pérot structures

Fast wavelength switching of a two-section slotted Fabry–PÉrot laser structure is presented. The slot design enables operation at five discrete wavelength channels spaced by 10 nm by tuning one section of the device. These wavelengths operate with sidemode suppression ratio in excess of 35 dB, and switching times between these channels of approximately 1 ns are demonstrated

Polarization matching design of InGaN-based semi-polar quantum wells-A case study of (11(2)over-bar2) orientation

We present a theoretical study of the polarization engineering in semi-polar III-nitrides heterostructures. As a case study, we investigate the influence of GaN, AlGaN, and AlInN barrier material on the performance of semi-polar (11 (2) over bar2) InGaN-based quantum wells (QWs) for blue (450 nm) and yellow (560 nm) emission. We show that the magnitude of the total built-in electric field across the QW can be controlled by the barrier material. Our results indicate that AlInN is a promising candidate to achieve (i) reduced wavelength shifts with increasing currents and (ii) strongly increased electron-hole wave function overlap, important for reduced optical recombination times. (C) 2014 AIP Publishing LLC

High-yield parallel transfer print integration of III-V substrate-illuminated C-band photodiodes on silicon photonic integrated circuits

Transfer printing is an enabling technology for the efficient integration of III-V semiconductor devices on a silicon waveguide circuit. In this paper we discuss the transfer printing of substrate-illuminated III-V C-band photodetectors on a silicon photonic waveguide circuit. The devices were fabricated on an InP substrate, encapsulated and underetched in FeCl3, held in place by photoresist tethers. Using a 2x2 arrayed PDMS stamp with a pitch of 500 mu m in x-direction and 250 mu m in y-direction the photodiodes were transfer printed onto DVS-BCB-coated SOI waveguide circuits interfaced with grating couplers. 83 out of 84 devices were successfully integrated

10Gbit/s modulation of a fast switching slotted Fabry-Pérot tunable laser

The device used is a three-section, 3mum wide ridge waveguide laser based on commercially available material. During the fabrication a series of slots are introduced into the front and back sections, which act as sites of internal reflections. The slots are etched to a depth that just penetrates the top of the upper waveguide resulting in an internal reflectance of-1% at each slot. The front, middle, and back sections are 180, 690 and 170 microns long respectively. In this work the back and middle sections are tied together electrically allowing simpler control of the device. By varying the applied DC currents, eight discrete channels are observed over a range of approximately 19nm

Broadband quantum dot micro-light-emitting diodes with parabolic sidewalls

Arrays of long wavelength, self-organized InGaAs quantum dot micron sized light-emitting diodes (mu-LEDs) with parabolic sidewalls are introduced. The parabolic profiles of the mu-LEDs produced by resist reflow and controlled dry etching improve the extraction efficiency from the LEDs by redirection of the light into the escape cone by reflection from the sidewalls. A fourfold increase in the substrate emitted power density compared to a reference planar LED is measured. The reflected light is verified to be azimuthally polarized. The spectral width of the emission can be greater than 200 nm. (C) 2008 American Institute of Physics. (DOI: 10.1063/1.2898731