Off-Area Bonding of HgCdTe Photoconductive Infrared Detectors using Tri-Layer Photolithography and Wet/Dry Etching Techniques

1996 ◽  
Vol 450 ◽  
Author(s):  
Sridhar Manthripragada ◽  
Kelley Hu ◽  
Frank Peters ◽  
Andre Burgess ◽  
Sachidananda Babu ◽  
...  

ABSTRACTOn-area wire bonding of HgCdTe photoconductive (PC) infrared detectors usually causes material damage underneath the bonding pads. Such damage may propagate into the active area, potentially degrading performance and posing long-term reliability problems. Some off-area bonding fabrication techniques can also induce some degree of semiconductor material damage. In this paper, we report a relatively straightforward off-area bonding scheme that solves these problems. The process uses multiple photolithography and chemical etching steps to create a continuous slope or staircase in the HgCdTe leading down to the epoxy surface. The staircase ensures smooth step coverage for the subsequent metalization. Tri-layer photolithography (resist /metal/resist) and reactive ion etching (RIE) is then used to remove the epoxy in the bonding pad area. Since all areas other than the pad region are protected by the metal film, no RIE radiation damage is induced to the active area. The contact metalization is achieved by using standard liftoff techniques. Our so called staircase off-area bonding fabrication technique can be used to fabricate highly reliable, high density, small-size, detector arrays.

1999 ◽  
Vol 575 ◽  
Author(s):  
H.-P. Brack ◽  
M. M. Koebel ◽  
A. Tsukada ◽  
J. Huslage ◽  
F. Buechi ◽  
...  

ABSTRACTWe have demonstrated earlier the useful performance of our PSI radiation-grafted membranes in terms of the current-voltage characteristics of 30 cm2 active area fuel cells containing these membranes and their long-term testing over 6,000 h at 60 °C. We report here on testing of PSI radiation-grafted membranes in these fuel cells at 80 °C and in short stacks comprised of two or four 100 cm2 active area cells. The in-situ degradation of membranes has been investigated by characterizing membranes both before testing in fuel cells and post-mortem after testing in fuel cells. Characterization was accomplished by means of ion-exchange capacity and infrared and Raman spectroscopic measurements. In addition, a rapid screening method for our ex-situ testing of the oxidative stability of proton-conducting membranes was developed in this work. Comparison of the initial screening test results concerning the oxidative stability of some perfluorinated, partially-fluorinated, and non-fluorinated membranes compare well qualitatively with the relative stability of these same membranes during their long-term testing in fuel cells.


2005 ◽  
Vol 483-485 ◽  
pp. 925-928 ◽  
Author(s):  
Roland Rupp ◽  
Michael Treu ◽  
Peter Türkes ◽  
H. Beermann ◽  
Thomas Scherg ◽  
...  

Other than open micropipes (MP), overgrown micropipes do not necessarily lead to a^significantly reduced blocking capability of the affected SiC device. However they can lead to a degradation of the device during operation. In this paper the physical structure of overgrown micropipes will be revealed and their contribution to the leakage current will be shown. The possible impact of the high local power dissipation in the surrounding of the overgrown micropipe will be discussed and long term degradation mechanisms will be described. Failure simulation under laboratory conditions shows a clear correlation between the position of overgrown micropipes and the location of destructive burnt spots.


1961 ◽  
Vol 1 (3) ◽  
pp. 199-208 ◽  
Author(s):  
R.R. Billups ◽  
W.L. Gardner

2007 ◽  
Author(s):  
Evangelos Theocharous ◽  
Jihong Fan ◽  
Xudong Li ◽  
Xiqi Hou ◽  
Bin Yang

Vacuum ◽  
2005 ◽  
Vol 80 (1-3) ◽  
pp. 218-222 ◽  
Author(s):  
J. Škriniarová ◽  
A. Perd’ochová ◽  
M. Hrúzik ◽  
M. Veselý ◽  
B. Bendjus ◽  
...  

2004 ◽  
Vol 824 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Vladimir M. Garbuzov ◽  
Alexander A. Kitsay ◽  
Vladimir A. Zirlin

AbstractTo investigate the behavior of monazite during accelerated radiation damage, which simulates effects of long term storage, 238Pu-doped polycrystalline samples of (La,Pu)PO4 and PuPO4 were synthesized for the first time ever and studied using powder X-ray diffraction (XRD) analysis and optical microscopy. The starting precursor materials were obtained by precipitation of La and (or) Pu from their aqueous nitrate solutions followed by calcination in air at 700°C for 1 hour, cold pressing, and sintering in air at 1200-1250°C for 2 hours. The 238Pu contents in ceramic samples measured using gamma spectrometry were (in wt.% el.): 8.1 for (La,Pu)PO4 and 7.2 for PuPO4. The (La,Pu)PO4 monazite remained crystalline at ambient temperature up to a cumulative dose of 1.19 × 1025 alpha decays/m3. In contrast, the PuPO4 monazite became nearly completely amorphous at a relatively low dose of 4.2 × 1024 alpha decays/m3. Swelling and crack formation due to the alpha decay damage was observed in the PuPO4 ceramic. Also, under self-irradiation this sample completely changed color from initial deep blue to black. The (La,Pu)PO4 monazite was characterized by a similar change in color from initial light blue to gray, however, no swelling or crack formation have so far been observed. The results of this study allow us to conclude that the radiation damage behavior of monazite strictly depends on the chemical composition. The justification of monazite-based ceramics as actinide waste forms requires additional investigation.


1981 ◽  
Vol 11 ◽  
Author(s):  
T. J. Headley ◽  
G. W. Arnold ◽  
C. J. M. Northrup

The long-term stability of nuclear waste forms is an important consideration in their selection for safe disposal of radioactive waste. Stability against long-term radiation damage is particularly difficult to assess by short-term laboratory experiments. Much of the displacement damage in high-level waste forms will be generated by heavy recoil nuclei emitted during the α-decay process of long-lived actinide elements. Hence, an accelerated aging test which reliably simulates the α-recoil damage accumulated during thousands of years of storage is desirable. One recent approach to this simulation is to implant the waste form with heavy Pb-ions.I- 6 If the validity of this approach is to be fully assessed, two important questions which have not yet been investigated must be answered.(1) Is the structural damage, including cumulative effects, similar for irradiation by Pb-ions and a-recoil nuclei in a given material? (2) Is the dose-dependence of the accumulated damage similar? The purpose of this investigation was to assess the extent of these similarities in selected materials. We utilized transmission electron microscopy (TEM) to characterize the radiation damage and measure its dose-dependence.


2017 ◽  
Vol 5 (10) ◽  
pp. 4818-4826 ◽  
Author(s):  
J.-P. Becker ◽  
B. Turan ◽  
V. Smirnov ◽  
K. Welter ◽  
F. Urbain ◽  
...  

We present a stand-alone integrated solar water-splitting device with an active area of 64 cm2 and a long-term stable operation. The modular setup of the device provides a versatile tool to integrate and evaluate various combinations of photoelectrodes and catalysts.


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