Design and fabrication of AlGaInP-based micro-light-emitting-diode
array devices
Xingzhen Bao
a,b
, Jingqiu Liang
a,
n
, Zhongzhu Liang
a
, Weibiao Wang
a
, Chao Tian
a
,
Yuxin Qin
a
, Jinguang Lü
a
a
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033,
China
b
University of Chinese Academy of Sciences, Beijing 100039, China
article info
Article history:
Received 16 June 2015
Received in revised form
29 August 2015
Accepted 10 September 2015
Keywords:
Light-emitting diodes
Arrays
Integrated optics devices
Microstructure fabrication
Substrate thickness
abstract
An integrated high-resolution (individual pixel size 80
μ
m 80
μ
m) solid-state self-emissive active
matrix programmed with 320 240 micro-light-emitting-diode arrays structure was designed and
fabricated on an AlGaInP semiconductor chip using micro electro-mechanical systems, microstructure
and semiconductor fabricating techniques. Row pixels share a p-electrode and line pixels share an
n-electrode. We experimentally investigated GaAs substrate thickness affects the electrical and optical
characteristics of the pixels. For a 150-
μ
m-thick GaAs substrate, the single pixel output power was
167.4
μ
W at 5 mA, and increased to 326.4
μ
W when current increase to 10 mA. The device investigated
potentially plays an important role in many fields.
& 2015 Elsevier Ltd. All rights reserved.
1. Introduction
Light-emitting-diodes (LEDs) are popular solid-state self-
emissive devices. With their intrinsic physical properties, low-
voltage operation characteristics, high efficiency, and reliability,
LEDs have long lifetimes and can be used at extreme conditions
such as at very high or low temperatures [1,2]. As they possess
such outstanding capabilities, LEDs are used in various applica-
tions such as traffic signals, automotive lighting, indoor/outdoor
illumination, warm white-light sources, and displays [3–6].
Micro-LED (
μ
LED) arrays are a type of LED device that have
emerged as a promising technology with many applications, in-
cluding self-emissive micro-displays, multi-site photo-stimulation
of nerve cells, military applications, biologic transducers, optical
biological chips, medical treatment, and biological neural net-
works [7–9]. Many micro-LED array devices that were built with
GaN epitaxial materials have been investigated. The luminescence
wavelengths of the GaN materials are predominately emitted at
blue and green wavebands. Moreover, GaN epitaxial materials
need to grow on a sapphire substrate, thus, anodes and cathodes
should be placed on one side on the device [10,11]. In order to
produce a full-color display for practical applications, the red
waveband must be included in addition to the blue and green
wavebands. As such, AlGaInP-based LEDs emitting in the yellow/
red spectral regions has been used extensively in everyday appli-
cations [12,13]. Unlike GaN prepared on a sapphire substrate, the
AlGaInP quaternary material system can be grown on precisely
lattice-matched GaAs substrates without generating many dis-
locations. For AlGaInP-based LEDs, the internal quantum efficiency
can be achieved by 99% [14–17]. Furthermore, anodes and
cathodes in these devices can be fabricated on two sides. It avoids
damaging chip due to GaAs substrate need not to peel off by laser
lift-off technology. For these reasons, in this paper, AlGaInP-based
materials are chosen as basal materials for fabricating red micro-
LED array devices.
Traditional methods for fabricating micro-LED arrays involve
arranging several single microchips onto a single substrate, fol-
lowed by fabrication of an electrode thread and encapsulation.
However, there are many disadvantages associated with these
traditional methods, such as inability to reduce the size of a single
pixel, diffi cultly when forming metal electrode threads, incon-
sistent light emission, and low resolution. Here, we report a
method that fabricates integrated micro-LED arrays on an AlGaInP
wafer using micro-electro-mechanical systems (MEMS) technol-
ogy and semiconductor fabricating technique. This integrated Al-
GaInP–micro-LED array device fabricated by MEMS technology
and semiconductor fabricating technique has a smaller size, higher
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/optlastec
Optics & Laser Technology
http://dx.doi.org/10.1016/j.optlastec.2015.09.016
0030-3992/& 2015 Elsevier Ltd. All rights reserved.
n
Corresponding author. Fax: þ 86 043186176920.
E-mail addresses: liangjq@ciomp.ac.cn (J. Liang), wangwbt@126.com (W. Wang).
Optics & Laser Technology 78 (2016) 34–41