2011 Vol. 40, No. 12
2011, 40(12): 2309-2313.
The electrical and metallurgical behavior of Ti/Pt/Au contacts on p-InP was investigated. The contacts were transformed to an ohmic contacts at the temperature about 450 ℃. Low resistance ohmic contacts (c=7.310-5cm2) were achieved after annealing at 450 ℃ for 4 minutes. To approach device process, Cr/Au (20 nm/400 nm) was deposited on the contact pads after the annealing process. The result indicates that the contacts of low resistance, smooth surface and high reliability are fabricated in a moderate condition. The auger electron spectroscopy(AES) depthcomposition profiles indicates that the Pt layer can relatively prevent Au from penetrating into the InP and only a small quantity of Au punched through the Pt layer and penetrated into the InP. The findings of the present study suggests that the formation of ohmic contacts on InP is controlled by chemical and metallurgical reaction between the contact metal and the InP layer, and a few InAux formations are beneficial to contact properties.
2011, 40(12): 2314-2322.
The main technology schemes, advantages, disadvantages and final results of three generations of domestic resistive arrays were reviewed andsummarized. The first generation of 64 64 resistive array was composed of bulk micromachined single crystal silicon membrane elements. The yield of resistors was acceptably high but the uniformity, power consumption performance, fill factor, format size and the compatibility of fabrication technology with CMOS process were very poor. The second generation of 128128 and 256256 resistive arrays were characterized of bulk micromachined multilayer resistor elements. With great improvements of process compatibility, uniformity and power consumption, the fill factor and format size were just increased to some limited extent. The third generation of 128 128 multilayer suspended membrane resistive array was fabricated by using membrane transfer technology, with the fill factor and power consumption performance greatly improved. This innovative technique still needs to be matured but is expected to be the mainstream fabrication technology for future domestic resistive arrays. In the end, the future technology developments of domestic resistive arrays were prospected, analyzed and discussed.
2011, 40(12): 2323-2327.
Lead zirconate titanate (PbZr0.3Ti0.7O3) thick films and single element detectors for pyroelectric applications were fabricated on Si (100) substrates by MEMS and screen-printing technology. The preparation method and device processing technology were studied in detail. Firstly, the silicon-cup was etched by tetra-methyl ammonium hydroxide (TMAH) solution. Secondly, the Al2O3 barrier layer was prepared to prevent Si diffusion between PZT/ Si through reactive radio frequency (RF) sputtering. Cool isostatic pressing experiments were conducted in order to increase the density of PZT thick films. Finally, the PZT ceramic thick films about 30 m were achieved at a low sintering temperature about 850 ℃. The dielectric permittivity and loss angle tangent tested at 1 kHz under 25℃ were 210 and 0.017 respectively. By using dynamic current method, pyroelectric coefficient of the PZT thick film was determined to be 1.5 10 -8 Ccm-2K-1. The detectivity of detector with 3 mm3 mm area was measured by mechanically chopped blackbody radiation as the function of frequency. The results show that the single element detector obtains its maximum detectivity 7.4107 cmHz1/2W-1 at 112.9 Hz.
2011, 40(12): 2328-2332.
Due to the non-uniformity of uncooled infrared focal plane arrays (IRFPA) shifting along with the variation of the application surrounding temperature, correction parameter must be updated frequently otherwise the correction quality would be degraded. Based on binary nonlinear non-uniformity theory model, a novel non-uniformity correction method considering surrounding temperature compensation was proposed. The implement procedure was described in detail. This approach takes into account both the responsive nonlinearity under the large dynamic range and the influence of surrounding temperature changes for non-uniformity. Quantitative test and comparison were performed among several correction technologies. Experimental test results show that the remainder non-uniformity corrected by proposal algorithm is less than 0.017%. This technique reduces the correction error largely. Real-time imaging indicates this method improve the image quality clearly. Furthermore, extends the application range of non-uniformity correction technology.
