Pixel-to-point transfer: A process for integrating individual GaN-based light-emitting devices in o heterogeneous microsystems

Z. S. Luo, T. Sands, N. W. Cheung, J. A. Chediak, J. Seo, L. P. Lee

Research output: Contribution to journalConference articlepeer-review


A novel ultra-low-thermal-budget pixel-to-point transfer process based on the excimer laser lift-off and Pd-In transient-liquid-phase bonding scheme was developed for flexible and precise placement of single pixels of GaN-based light-emitting diodes (LED) on target substrates. The transfer was accomplished by (1) temporarily bonding the light-emitting diode (LED) pixel to a specially designed pick-up rod with sapphire substrates facing up using Super Glue®, (2) removing the sapphire substrates using laser lift-off, and (3) registering and permanently bonding the LED pixel to the designated area in the target substrates using Pd-In transient-liquid-phase bonding. An oxygen plasma was employed to remove the Super Glue® residue before further microfabrication and system integration was performed. The capability of this technique was demonstrated in the integration of GaN-based LED pixels with pro-fabricated PIN photodiode chips and thin-film bandedge filters, which formed the non-disposable subsystems of a fluorescence-based lab-on-a-chip system. The performance of these integrated LED pixels and the integrated microsystems has been assessed by evaluating the fluorescence intensity as a function of equivalent fluorescein dye concentration using disposable polydimenthyl siloxane(PDMS) microfluidic channels. GaN LEDs with peak emission at 463 nm were used to excite 515nm fluorescence from FluoSpheres® carboxylate-modified fluorescent microspheres (40nm in diamters).

Original languageEnglish
Pages (from-to)117-121
Number of pages5
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 2003
EventIntegration of Heterogeneous Thin-Film Materials and Devices - San Francisco, CA, United States
Duration: 23 Apr 200324 Apr 2003


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