Study of Deep Levels in Mesa-Type HgCdTe Device

Abstract

The deep levels in the p+-on-n mesa-type Hg1-xCdxTe (x=0.222) device fabricated on the Si substrate by the molecular beam epitaxy method have been studied using the isothermal capacitance transient spectroscopy (ICTS) method and the spectral analysis of deep level transient spectroscopy (SADLTS) method. The value of the activation energy and the capture cross section could not be determined by means of ICTS because the apparent peaks were not obtained in the ICTS spectrum. However, five deep levels have been confirmed by SADLTS and the activation energies and the capture cross sections for each level were calculated. The confirmed levels existed from 19.7 meV to 45.7 meV below the conduction band edge. Three deeper levels are considered to be related to the Hg vacancy, whereas two shallower levels are considered to be related to the impurity in the n-type region. Moreover it is suggested that three deeper levels may assist the tunneling current in the reverse bias region. On the other hand, the obtained values of the capture cross sections ranged from 10-18 to 10-11 cm2.