Analysis of the dark current of focal-plane-array Hg1-xCdxTe diode

Experimental results are presented for current-voltage and dynamic resistan ce-voltage characteristics of Hg1-xCdxTe ion-implanted p-n junction photodi odes with x=0.22. By measuring the temperature dependence of the de charact eristics in the temperature range 25-140 K, the dark current mechanisms are studied. It was found that the dark currents can be represented with three current components over a broad range of voltage and temperature, i.e. dif fusion, trap-assisted tunneling and band-to-band tunneling. The noise current versus frequency at different reverse bias was measured. The 1/f noise in HgCdTe photodiode has been studied as a function of temper ature, diode bias and dark current. The temperature dependence of the 1/f n oise was found to be the same as those of the surface generation and leakag e currents. The photo response spectra were measured. The maximum specific detectivity (D-lambda*) value and the maximum signal-to-noise ratio are abo ut 3.51 x 10(10) cm Hz(1/2)/W and 5096 at 50 mV reverse bias, respectively. Finally, an 1 x 128 hybrid Hg1-xCdxTe focal plane array with x=0.22 was fa bricated. The histograms of quantum efficiency of the focal plane array are present. The mean quantum efficiency and detectivity D-lambda* are 57.7% a nd 4.03 x 10(10) cm Hz(1/2)/W respectively. (C)2000 Elsevier Science S.A. A ll rights reserved.