Molecular beam epitaxial InSb infrared photodiode with low dark current

Abstract

The InSb epitaxial layer of p+-n-n+ structure was grown by Molecular Beam Epitaxy (MBE) on a heavily doped InSb substrate. Photodiodes of InSb were fabricated by standard semiconductor manufacturing process. Measurement and analysis of its electrical properties was carried out. Compared with traditional bulk crystal InSb of p+-n structure, we find that, when the external bias voltage is 0.1V, dark current density values of p+-n-n+ InSb device and InSb bulk material device is 1.1×10-6 A·cm-2 and 9.5×10-5 A·cm-2 at 77K, respectively. zero-bias-resistance area products is 8.9×104Ω·cm2 and 6.2×103 Ω·cm2 at 77K, respectively. Doping concentrations values in the absorption layers are equal to 5.0×1014 cm-3 and 1.3×1016 cm-3 , respectively. The InSb epitaxial layer of p+-n-n+ structure which has better crystal quality achieves better performance than bulk crystal InSb when the passivation process is reliable. It provides an important foundation for the fabrication of epitaxial InSb infrared detector.