Atomic-layer-deposited Al2O3 and HfO2 on GaN: A comparative study on interfaces and electrical characteristics

作者：Chang Y C; Huang M L; Chang Y H; Lee Y J; Chiu H C; Kwo J^*; Hong M

来源：Microelectronic Engineering, 2011, 88(7): 1207-1210.

DOI：10.1016/j.mee.2011.03.098

• MOS
• Atomic-layer-deposition (ALD)
• HfO2
• Al2O3
• GaN
• High k dielectric

Al2O3, HfO2, and composite HfO2/Al2O3 films were deposited on n-type GaN using atomic layer deposition (ALD). The interfacial layer of GaON and HfON was observed between HfO2 and GaN, whereas the absence of an interfacial layer at Al2O3/GaN was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy. The dielectric constants of Al2O3, HfO2, and composite HfO2/Al2O3 calculated from the C-V measurement are 9, 16.5, and 13.8, respectively. The Al2O3 employed as a template in the composite structure has suppressed the interfacial layer formation during the subsequent ALD-HfO2 and effectively reduced the gate leakage current. While the dielectric constant of the composite HfO2/Al2O3 film is lower than that of HfO2, the composite structure provides sharp oxide/GaN interface without interfacial layer, leading to better electrical properties.

• 出版日期2011-7
• 单位清华大学