Akademik Veri Yönetim Sistemi
3rd International Conference on Material Science and Nanotechnology, Rome, İtalya, 3 - 06 Ekim 2022, ss.34
Germanium
(Ge) is a promising material platform to realize monolithically integrated
laser that could enable the fully integrated infrared systems for a variety of applications
ranging from optical communication to biosensing. The pseudo-direct bandgap of
Ge can be engineered via the application of tensile strain, where direct
bandgap Ge has been reported by several research groups for both uniaxial (in
[100] direction) and biaxial (in (100) plane) strain types. In this work, for
the first time, we fabricated tensilely strained single crystalline Ge
microstructures through liquid phase epitaxy in a CMOS-compatible fashion and
record-high strain level, as high as 2.4%, has been demonstrated in the [110]
direction. The fabrication of the suspended microstructures on silicon is based
on an environmentally friendly, room-temperature operated physical vapor
deposition tool, namely sputter, where the deposited amorphous Ge is
crystallized after a rapid thermal annealing (RTA) process. RTA both enables crystallization
of Ge and converts the capping layer into a stressor. The subsequent
photolithography process enables to fabricate suspended Ge microstructures with
uniaxial tensile strain along the crystallization direction, where strain is
transferred from the underetched stressor into the suspended parts of Ge. The
strain enhances as the underetched portion of the stressor is increased as
verified through the micro-Raman measurements. The fabricated microstructures
demonstrate room-temperature light emission, and the emission both red-shifts
and enhances with increasing strain as expected. Furthermore, these
experimental observations are verified by 3-dimensional finite element methods
calculations.