HgCdTe photovoltaic detectors fabricated using a new junction formation technology

The current-voltage characteristics measured over a wide temperature range are reported for HgCdTe mid-wavelength infrared n-on-p photodiodes fabricat ed using a novel junction formation technology. The planar homojunction dev ice junctions were formed on LPE grown vacancy doped HgCdTe using a reactiv e ion etching (RIE) plasma induced conversion process. The zero bias dynami c resistance-junction area product, R(0)A, was 4.6 x 10(7) Ohm cm(2) at 80 K and is comparable to the best planar diodes reported using conventional i on implantation junction formation technology. Arrhenius plots of R(0)A exh ibit an activation energy equal to the bandgap, E-g, and show that the diod es are diffusion limited for temperatures greater than or equal to 135 K. A series of temperature dependent 1/f noise measurements were performed, ind icating that the activation energy for 1/f noise in the region where the di odes are diffusion limited is 0.7 E-g. Energies close to this value have pr eviously been associated with Hg vacancies in HgCdTe. These results are sim ilar to those obtained from high quality HgCdTe photodiodes fabricated usin g mature ion implantation technology. However, the plasma based technology used in this work is significantly less complex and does not require any hi gh temperature annealing steps. (C) 2000 Elsevier Science Ltd. All rights r eserved.