Abstract
In this work, we have connected the SPM chamber to MBE system, and this in-situ SPM system has provided the result including GaAs(100)-(2x4) surface, GaAs(100)-(4x6) surface, and the surface of ALD-Al2O3 on GaAs.The smooth surface of GaAs had been achieved through MBE technique, and the interesting surface structure had been observed. The STS spectra also show that the GaAs(100)-(2x4) and GaAs(100)-(4x6) surface have different distribution of DOS to induce “flat” spectra. Finally, we had revealed the morphology and STS of one cycle ALD-Al2O3 on n-type and p-type GaAs, and the spectra indicate that the ALD Al2O3 induces large DOS near conduction band and valence band, and it can’t erase the effect came from GaAs. According to above data, we build the model of distribution of DOS for GaAs and ALD-Al2O3/GaAs to explain the different performance between p and n type MOS. Finally, we compare the STS between ALD-Al2O3/GaAs and MBE- Gd2O3/GaAs, and the STS of later imply that Gd2O3 maybe can cancel the effect came from GaAs to induce ‘flat spectrum’.