Byun Young-Chul, Choi Sungho, An Youngseo, McIntyre Paul C, Kim Hyoungsub
School of Advanced Materials Science and Engineering, Sungkyunkwan University , Suwon 440-746, Korea.
ACS Appl Mater Interfaces. 2014 Jul 9;6(13):10482-8. doi: 10.1021/am502048d. Epub 2014 Jun 18.
We investigated ZnO surface passivation of a GaAs (100) substrate using an atomic layer deposition (ALD) process to prepare an ultrathin ZnO layer prior to ALD-HfO2 gate dielectric deposition. Significant suppression of both Ga-O bond formation near the interface and As segregation at the interface was achieved. In addition, this method effectively suppressed the trapping of carriers in oxide defects with energies near the valence band edge of GaAs. According to electrical analyses of the interface state response on p- and n-type GaAs substrates, the interface states in the bottom half of the GaAs band gap were largely removed. However, the interface trap response in the top half of the band gap increased somewhat for the ZnO-passivated surface.
我们利用原子层沉积（ALD）工艺研究了GaAs（100）衬底的ZnO表面钝化，以便在ALD-HfO2栅极电介质沉积之前制备超薄ZnO层。实现了对界面附近Ga-O键形成和界面处As偏析的显著抑制。此外，该方法有效地抑制了能量接近GaAs价带边缘的氧化物缺陷中载流子的俘获。根据对p型和n型GaAs衬底上界面态响应的电学分析，GaAs带隙下半部分的界面态被大量去除。然而，对于ZnO钝化表面，带隙上半部分的界面陷阱响应有所增加。
