Transferring of GaAs microtips using selective wet etching Al0.7Ga0.3As sacrificial layer

• Published in: Microelectronic engineering Vol. 85; no. 7; pp. 1481 - 1483
• Main Authors: Sun, Xiaojuan, Hu, Lizhong, Zhang, Hongzhi, Tian, Yichun, Liang, Xiuping, Zhang, Heqiu, Pan, Shi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 01.07.2008
• Subjects: Applied sciences; Compound structure devices; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Microelectronic fabrication (materials and surfaces technology); Physics; Scanning probe microscopes, components and techniques; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; LPE; Scanning electron microscopy; Sandwich structure; Etching; Negative resist; MOCVD; Scanning near field optical microscopy; Transfer processing; Liquid phase epitaxy; Microelectronic fabrication; Wet process; Selective epitaxy; Selective growth; Adhesive joint; Selective etching; Positive resist; Semiconducting allium arsenide; Wafer; Sacrificial layer; Damaging
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2007.11.002

GaAs pyramidal microtips were successfully transferred from GaAs substrate to target wafer by a simple technique, i.e., selective wet etching off AlGaAs sacrificial layer. A GaAs/Al0.7Ga0.3As/GaAs sandwich structure is firstly formed on GaAs (0 0 1) substrate by metalorganic chemical vapor deposition, and then GaAs pyramidal microtips are grown on the sandwich structure using selective liquid-phase epitaxy. The GaAs microtips are removed from the sandwich structure by selective wet etching Al0.7Ga0.3As layer using concentrated HCl solution. Finally, the tips are glued onto the target wafer by a negative photoresist. During this transfer process the tips are completely encapsulated in a positive photoresist to protect against attack. Scanning electron microscopy images show that GaAs tips can be successfully transferred without any damage by this technique. The achievement reported here represents a significant step towards the application of scanning near-field optical microscopy.