The Atomic Layer Etching Technique with Surface Treatment Function for InAlN/GaN Heterostructure

Crystals

Jiaqi He¹  Yang Jiang¹  Xinyi Tang¹  Fangzhou Du¹  Honghao Lu¹  Chuying Tang¹  Qiaoyu Hu¹  Kangyao Wen¹  Hongyu Yu¹  Qing Wang¹  Zhanxia Wu²  Haimin Hong² 

[1] School of Microelectronics, Southern University of Science and Technology, Shenzhen 518055, China;Shenzhen Smartchip Microelectronics Technology Co., Ltd., Shenzhen 518045, China;

关键词: InAlN/GaN heterostructure;    atomic layer etching;    under-etching;    indium clustered;    surface treatment;    two-dimensional electron gas density;   

DOI  :  10.3390/cryst12050722

来源: DOAJ

【 摘 要 】

This paper studied an atomic layer etching (ALE) technique with a surface treatment function for InAlN/GaN heterostructures with AlN spacer layers. Various parameters were attempted, and 30 s O₂ + 15 W BCl₃ was chosen as the optimal recipe. The optimal ALE approach exhibited satisfactory etching results, with regard to the etch-stop effect, compared with other techniques. The atomic force microscopy (AFM) results showed an etching per cycle (EPC) value of 0.15 nm/cycle, with a 0.996 fit coefficient and root mean square (RMS) surface roughness of around 0.61 nm (0.71 nm for as-grown sample), which was the lowest in comparison with digital etching (0.69 nm), Cl₂/BCl₃ continuous etching (0.91 nm) and BCl₃ continuous etching (0.89 nm). X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy with energy dispersive X-ray spectroscopy measurements (STEM/EDS) verified the indium clustered phenomena at the bottom apex of V-pit defects in the epi structure of InAlN/GaN high electron mobility transistors (HEMTs) for the first time, in addition to the surface morphology optimization for the ALE under-etching technique used in this work. The resistor hall effect (Hall) and AFM measurements demonstrated that after 4 or 5 ALE cycles, the two-dimensional electron gas (2-DEG) density and RMS roughness were improved by 15% and 11.4%, respectively, while the sheet resistance (R_sh) was reduced by 6.7%, suggesting a good surface treatment function. These findings were important for realizing high-performance InAlN/GaN HEMTs.

【 授权许可】

Unknown