Segregation and formation of MnP particles during rapid thermal annealing of Mn-implanted InP and GaP

Abstract

We have studied the structural and magnetic properties of Mn implanted (1-5× 1016 cm-2, 200 keV) into InP and GaP substrates, before and after rapid thermal annealing. As revealed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, and transmission electron microscopy measurements, implantation results in an amorphous surface layer 300 nm deep, and subsequent annealing gives rise to epitaxial recrystallization of this layer accompanied by a segregation of most of the Mn into clusters about 60 nm in diameter at the surface. Magnetic measurements indicate ferromagnetic behavior only for the annealed samples with TC close to 290 K, characteristic of bulk MnP, whose presence is confirmed by diffraction data. In addition, there is no evident dependence of the magnetic and structural properties on the doping type or level of the substrates. © 2009 American Institute of Physics.