IDENTIFICATION OF RESIDUAL IMPURITIES IN SI-DOPED MBE GROWN GAAS

The changes of dopant vaporization enthalpy in GaAs:Si grown by molecu lar beam epitaxy revealed the presence of residual donors related to g roup VI elements. This has been confirmed by deep level transient spec troscopy studies of AlGaAs:Si layers grown in the same MBE system. It is argued that a commonly observed deep trap labelled E2 is probably r elated to Te, Se or S. The measurements have been performed on near-id eal Al Schottky barriers grown in situ by MBE.