Photocurrent contrast in semi-insulating Fe-doped InP

Abstract

The relation between photocurrent and iron distribution in as-grown bulk InP is studied on the basis of a theoretical model that considers the electronic transitions involving Fe 2+ ( 5 E) and Fe 3+ electronic levels. The photocurrent contrast is thus analysed in terms of fluctuations in [Fe 2+ ] and [Fe 3+ ]. When studying the homogeneity of Fe-doped semi-insulating InP wafers by means of scanning extrinsic photocurrent microscopy, it is seen that inhomogeneity is mainly controlled by fluctuations of the neutral iron concentration [Fe 3+ ].

Observation of Fe-related defects in neutron irradiated semi-insulating InP

“…According to the present technology, semi-insulating ͑SI͒ InP is achieved by doping the liquid encapsulated Czochralski ͑LEC͒ material with Fe, which acts as a deep acceptor and compensates the residual shallow donors. 2,3 However, there are still some open questions concerning the characterization of the electrical and optical properties of InP when an amount of iron is incorporated into the lattice. For example, Fe concentration must be higher than the residual shallow donors in order to render a semi-insulating material.…”