THE EFFECT OF NITROGEN-IONS EMITTED FROM A PLASMA SOURCE ON MOLECULAR-BEAM EPITAXIAL-GROWTH OF P-ZNSE-N

Excited neutral nitrogen species emitted from a rf plasma source were characterized by the laser-induced fluorescence (LIF) spectroscopy, wh ile nitrogen ions were detected by the ion counting method, The LIF in tensity for nitrogen molecules increases monotonously up to the rf pow er of 100 W and saturates over 100 W. On the contrary, ion count of ni trogen ions shows a gradual increase up to 100 W, then rapidly increas es above 100 W. The correlation between the number of excited nitrogen species and the net acceptor concentration (N-A --> N-D) of nitrogen doped ZnSe epitaxial layers for various rf powers has been studied. We confirm that the excited neutral nitrogen molecules are effective for acceptor doping, while nitrogen ions enhance carrier compensation pre sumably due to degradation of crystal quality. We show that the activa tion ratio {(N-A-N-D)/[N]} of p-ZnSe:N is greatly improved by removing ions from the nitrogen plasma. (C) 1997 American Institute of Physics .