Investigation of a 4H-SiC metal-insulation-semiconductor structure with an Al2O3/SiO2 stacked dielectric

• 来源期刊: 中国物理B（英文版）
• 关键词: 4H-SiC Al2O3 high-k dielectric
• 年，卷（期）: 2012,（8）
• 页码范围: 494-497
• 页数: 4页
• 语种: 英文
• DOI: 10.1088/1674-1056/21/8/087701

摘要

Atomic layer deposited (ALD) Al2O3/dry-oxidized ultrathin SiO2 films as a high-k gate dielectric grown on 8° off-axis 4H-SiC (0001) epitaxial wafers are investigated in this paper.The metal-insulation-semiconductor (MIS) capacitors,respectively with different gate dielectric stacks (Al2O3/SiO2,Al2O3,and SiO2) are fabricated and compared with each other.The I-V measurements show that the Al2O3/SiO2 stack has a high breakdown field (≥12 MV/cm)comparable to SiO2,and a relatively low gate leakage current of 1 × 10-7 A/cm2 at an electric field of 4 MV/cm comparable to Al2O3.The 1-MHz high frequency C-V measurements exhibit that the Al2O3/SiO2 stack has a smaller positive flat-band voltage shift and hysteresis voltage,indicating a less effective charge and slow-trap density near the interface.