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Watanabe, Kenta*; Yamada, Takahiro*; Nozaki, Mikito*; Nakazawa, Satoshi*; Shih, H.*; Anda, Yoshiharu*; Ueda, Tetsuzo*; Yoshigoe, Akitaka; Hosoi, Takuji*; Shimura, Takayoshi*; et al.
no journal, ,
Initial oxidation process of AlGaN surface during thermal oxidation was investigated by synchrotron radiation photoelectron spectroscopy. Thermal oxidation of AlGaN/GaN/Si(111) substrates was carried out for 30 min in the temperature range from 200 to 1000 degrees in O
ambient. The obtained Ga 2p spectra exhibited peak shift toward the higher binding energy with increasing oxidation temperature, suggesting the growth of Ga oxides on AlGaN surface. The peak deconvolution of Ga 2p spectra into Ga-O and Ga-N components revealed that the formation of Ga oxides was formed on AlGaN surface at above 400 degrees while GaN surface was stable below 600 degrees. These results indicate that AlGaN surface is easy to be oxidized compared to GaN surface.
Nozaki, Mikito*; Watanabe, Kenta*; Yamada, Takahiro*; Shih, H.*; Nakazawa, Satoshi*; Anda, Yoshiharu*; Ueda, Tetsuzo*; Yoshigoe, Akitaka; Hosoi, Takuji*; Shimura, Takayoshi*; et al.
no journal, ,
We fabricated AlON dielectric films by repeating thin AlN deposition and in situ O
oxidation for AlGaN/GaN MOS-HFETs. Uniform nitrogen distribution is achievable by the proposed ALD-based process and that nitrogen concentration can be precisely controlled by changing AlN thickness (ALD cycle number) in each step. It was found that AlON films grown by ALD system offers significant advantages in terms of practical application while keeping superior Vth stability and electrical properties at the insulator/AlGaN interface in AlGaN/GaN MOS-HFETs.
/AlGaN interface property deposited by PECVDTerashima, Daiki*; Watanabe, Kenta*; Yamada, Takahiro*; Nozaki, Mikito*; Shih, H.*; Nakazawa, Satoshi*; Anda, Yoshiharu*; Ueda, Tetsuzo*; Yoshigoe, Akitaka; Hosoi, Takuji*; et al.
no journal, ,
Impact of input power and substrate temperature of SiO deposition by plasma-enhanced CVD on SiO/AlGaN interface was investigated by means of electrical characterization of MOS capacitors. Synchrotron radiation photoemission spectroscopy revealed that Ga oxide component on AlGaN surface increases with increasing input power of PECVD. MOS capacitors with SiO gate insulator deposited at low input power shows relatively better SiO/AlGaN interface quality, despite degraded interface quality for the sample with SiO deposited at high input power. These results suggest that AlGaN surface oxidation during oxide deposition should be controlled to obtain good interface property.