As an option to traditional positive or negative photoresist, hybrid resist has been developed to provide an alternative way to create small trench features, at the range of 20-60 nm, by generating with a single expose, with both positive and negative responses to TMAH developer in one resist layer.  Here we report the design and development of a series of frequency-doubling KrF hybrid resists for an Extremely Thin Silicon on Insulator (ETSOI) dual-isolation application for 20 nm node and beyond. The resist formulations were optimized in terms of photo-acid generators (PAGs), PAG loading level and polymers. The resulting KrF hybrid resists are compatible with conventional KrF lithography processes, including conventional illumination, binary masks and 0.26 N TMAH developer, to afford a spacewidth of 20-60 nm. The space CD can be controlled by means of formulation and process options, but is insensitive to expose dose and mask CD. On integrated wafers, the hybrid resists have demonstrated good lithography performance, including through-pitch CD uniformity, focus/expose process window, profile, LER and RIE behavior. This hybrid resist process has been used to fabricate initial development structures for high performance dual-isolation ETSOI devices.
For about ten years, we have been developing InP on Si devices under different projects focusing first on
μlasers then on semicompact lasers. For aiming the integration on a CMOS circuit and for thermal issue, we relied
on SiO2 direct bonding of InP unpatterned materials. After the chemical removal of the InP substrate, the
heterostructures lie on top of silicon waveguides of an SOI wafer with a separation of about 100nm. Different
lasers or photodetectors have been achieved for off-chip optical communication and for intra-chip optical
communication within an optical network. For high performance computing with high speed communication
between cores, we developed InP microdisk lasers that are coupled to silicon waveguide and produced 100μW of
optical power and that can be directly modulated up to 5G at different wavelengths. The optical network is based
on wavelength selective circuits with ring resonators. InGaAs photodetectors are evanescently coupled to the
silicon waveguide with an efficiency of 0.8A/W. The fabrication has been demonstrated at 200mm wafer scale in
a microelectronics clean room for CMOS compatibility. For off-chip communication, silicon on InP evanescent
laser have been realized with an innovative design where the cavity is defined in silicon and the gain localized in
the QW of bonded InP hererostructure. The investigated devices operate at continuous wave regime with room
temperature threshold current below 100 mA, the side mode suppression ratio is as high as 20dB, and the fibercoupled
output power is ~7mW. Direct modulation can be achieved with already 6G operation.
In this article, we report on long wavelength (1.27 μm) single-mode micro-structured photonic crystal strained InGaAs
quantum wells VCSELs for optical interconnection applications. Single fundamental mode room-temperature
continuous-wave lasing operation was demonstrated for devices designed and processed with different two-dimensional
etched patterns. The conventional epitaxial structure was grown by Metal-Organic Vapor Phase Epitaxy (MOVPE) and
contains fully doped GaAs/AlGaAs DBRs, one oxidation layer and three strained InGaAs quantum wells. The holes were
etched half-way through the top-mirror following various designs (triangular and square lattices) and with varying hole's
diameters and pitches.
We obtained up to 1.7 mW optical output power and more than 30 dB Side-Mode Suppression Ratio (SMSR) at
room temperature and in continuous wave operation. Systematic static electrical, optical and spectral characterization
was performed on wafer using an automated probe station. Numerical modeling using the MIT Photonic-Bands (MPB
) package of the transverse modal behaviors in the photonic crystal was performed using the plane wave method in
order to understand the index-guiding effects of the chosen patterns, and to further optimize the design structures for
mode selection at the given wavelength.
In this article, we present our results on long wavelength (1.1 μm) single-mode micro-structured photonic crystal
strained InGaAs quantum wells VCSELs for optical interconnection applications. Single fundamental mode roomtemperature
continuous-wave lasing operation was demonstrated for devices designed and processed with a number of
different two-dimensional etched patterns. The conventional epitaxial structure was grown by Molecular Beam Epitaxy
(MBE) and contains fully doped GaAs/AlGaAs DBRs, one oxidation layer and three strained InGaAs quantum wells.
The holes were etched half-way through the top-mirror following various designs (triangular and square lattices) and
with varying hole's diameters and pitches.
At room temperature and in continuous wave operation, micro-structured 50 µm diameter mesa VCSELs with
10 μm oxidation aperture exhibited more than 1 mW optical power, 2 to 5 mA threshold currents and more than 30 dB
side mode suppression ratio at a wavelength of 1090 nm. These structures show slight power reduction but similar
electrical performances than unstructured devices. Systematic static electrical, optical and spectral characterization was
performed on wafer using an automated probe station. Numerical modeling using the MIT Photonic-Bands (MPB )
package of the transverse modal behaviors in the photonic crystal was performed using the plane wave method in order
to understand the index-guiding effects of the chosen patterns, and to further optimize the design structures for mode
selection at extended wavelength range.
In this article, we report our results on 1.3&mgr;m VCSELs for optical interconnection applications. Room
temperature continuous-wave lasing operation is demonstrated for top emitting oxide-confined devices with three
different active materials, highly strained InGaAs/GaAs(A) and GaInNAs/GaAs (B) multiple quantum wells (MQW) or
InAs/GaAs (C) quantum dots (QD). Conventional epitaxial structures grown respectively by Metal Organic Vapour
Phase Epitaxy (MOVPE), Molecular Beam Epitaxy (MBE) and MBE, contain fully doped GaAs/AlGaAs DBRs. All
three epilayers are processed in the same way. Current and optical confinement are realized by selective wet oxidation.
Circular apertures from 2 (micron)m to 16 (micron)m diameters are defined.
At room temperature and in continuous wave operation, all three systems exhibit lasing operation at
wavelengths above 1 275nm and reached 1 300nm for material (A). Typical threshold currents are in the range [1-
10]mA and are strongly dependent firstly on oxide diameter and secondly on temperature. Room temperature cw
maximum output power corresponds respectively to 1.77mW, 0.5mW and 0.6mW. By increasing driving current,
multimode operation occurs at different level depending on the oxide diameter. In case (A), non conventional modal
behaviors will be presented and explained by the presence of specific oxide modes.
Thermal behaviors of the different devices have been compared. In case (A) and (C) we obtain a negative T0.
We will conclude on the different active materials in terms of performances with respect to 1300nm VCSEL
In the field of datacom, 10 Gbit/s sources with a good coupling in monomode silica fibers, whose
dispersion minimum occurs at 1.3 μm, are required. Vertical Cavity Surface Emitting Lasers (VCSELs)
emitting at 1.3 μm are key components in this field thanks to their compactness, their ability of being
operated at high frequencies, their low threshold current and their low beam divergence. Such devices
emitting in this wavelength range have been demonstrated using different materials such as strained
GaInAs/GaAs quantum wells [1-3], GaInNAs/GaAs quantum wells [4-7], InAs/GaAs quantum dots [8,
9], and antimonides , using either molecular beam epitaxy (MBE) or metalorganic vapor phase
In the emerging field of photonics on CMOS, there is a need to bond efficient III-V laser sources on SOI wafers. These components should operate at small voltage and current, have a small footprint, and be
efficiently couple to Si waveguides, these latter being transparent above 1.1 μm. Since these
requirements resemble VCSEL properties, the development of VCSEL emitting above 1.1 μm could
therefore benefit to future new sources for photonics on silicon applications.
In this context we developed GaAs-based VCSELs emitting in the 1.1 μm - 1.3 μm range with
GaInAs/GaAs or GaInNAs/GaAs quantum wells (QWs) as the active materials.