Structural Modifications in Free-Standing InGaN/GaN LEDs after Femtosecond Laser Lift-Off
Steffen Bornemann,
Nursidik Yulianto,
Tobias Meyer,
Jan Gülink,
Christoph Margenfeld,
Michael Seibt,
Hutomo Suryo Wasisto,
Andreas Waag
Affiliations
Steffen Bornemann
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
Nursidik Yulianto
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
Tobias Meyer
IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
Jan Gülink
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
Christoph Margenfeld
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
Michael Seibt
IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
Hutomo Suryo Wasisto
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
Andreas Waag
Institute of Semiconductor Technology (IHT) and Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany
A laser lift-off (LLO) process has been developed for detaching thin InGaN/GaN lightemitting diodes (LED) from their original sapphire substrates by applying an ultrafast laser. LLO is usually based on intense UV irradiation, which is transmitted through the sapphire substrate and subsequently absorbed at the interface to the epitaxially grown GaN stack. Here, we present a successful implementation of a two-step LLO process with 350 fs short pulses in the green spectral range (520 nm) based on a two-photon absorption mechanism. Cathodo- and electroluminescence experiments have proven the functionality of the LLO-based chips. The impact of radiation on the material quality was analysed with scanning (SEM) and transmission electron microscopy (TEM), revealing structural modifications inside the GaN layer in some cases.
