HgCdTe/CdZnTe LPE epitaxial layers: from material growth to applications in devices

Abstract Some properties of liquid phase epitaxy growth of Hg1-xCdxTe/Cd1-yZnyTe epiwafers (x≈0.21; 0.3 and y≈0.04 by mole fraction) applicable for mid- and long wavelength infrared (IR) photodiodes and focal plane arrays (FPA) are described. The design and technology of infrared photodetectors manufacturing, both single and multielements arrays with different sizes of sensitive elements, have been developed. Experimentally determined are the low-temperature regimes (T ≤ 100 °C) of CdTe passivation layers growth by hot wall epitaxy method and regimes of thin metallic contact layers deposition by vacuum thermal and magnetron sputtering techniques. From measured current-voltage characteristics of formed HgCdTe photodiodes with area ∼(0.4-0.8)×10−4 cm2 the value of detectivity was estimated as D*=2.67·1010 cm·W−1·Hz1/2 for long wavelength photodiodes. NETD for 320x256 mid IR FPAs with junction area 10x10 µm2 and pitch 15µm was 15-22 mK.