STRUCTURAL-PROPERTIES OF ZN-DIFFUSED INP LAYERS

A sealed tube method has been adopted to prepare Zn-diffused InP layer s. Both Zn3P2 and Zn+InP have been used as sources. The samples were p repared at 500 degrees C. The diffusion time ranged from 5 up to 120 m in. Both S- and Zn-doped InP crystals have been used as substrates. Th e Zn depth profile has been measured by secondary ion mass spectroscop y, while the lattice strain produced by diffusion has been carefully i nvestigated by x-ray double crystal diffraction and the standing-waves method of recording photoelectrons. The results show that in the S-do ped crystal the diffused/virgin interface is very sharp and the diffus ed layers are lattice contracted. The concentration of Zn, as well as the lattice strain, do not depend on the diffusion time, whereas the t hickness of the diffused layer increases with time. The plot of diffus ed layer thickness versus the square root of the diffusion time showed different slopes depending on the diffusion sources. Both lattice str ain and diffusion depth depend on the diffusion source, whereas the co ncentration of Zn is not influenced by the type of diffusion source. ( C) 1997 American Institute of Physics.