2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session B5: Heterogeneous Integration on Silicon
11:15 AM–2:15 PM,
Monday, March 16, 2009
Room: 401/402
Sponsoring
Unit:
FIAP
Chair: Ganesh Samudra, National University of Singapore
Abstract ID: BAPS.2009.MAR.B5.3
Abstract: B5.00003 : Heterogeneous Integration of Materials on Si for Nanophotonics Devices
12:27 PM–1:03 PM
Preview Abstract
Abstract
Author:
Solomon Assefa
(IBM T.J. Watson Research Center)
Optical interconnects are attractive candidates for achieving
communication
bandwidth well beyond terabit-per-second for high-performance
multi-core
microprocessors. Silicon has become a desirable material due to its
transparency in the infrared wavelength range and the ease for
integrating
optical devices at the vicinity of CMOS circuitry utilizing standard
processes. While state-of-the-art patterning techniques provide
precise
dimension control as well as pattern placement, standard doping and
metallization steps enable utilization of phenomena such as carrier
injection and depletion to render the devices tunable. As a
result, large
progress has been made on Si-based nanophotonic devices such as
modulators,
switches, and wavelength division multiplexing (WDM) systems [1, 2].
To make photodetectors, however, a heterogeneous integration of
other
materials that absorb light in the infrared is necessary.
Available in
standard front-end CMOS processes for gate strain engineering,
Germanium is
suitable due to its high absorption coefficient at 1.3$\mu $m and
1.5$\mu $m
wavelengths. Thus, Ge can be directly integrated into the process to
fabricate compact photodetectors simultaneously with amplifier
circuits in
order to make a receiver for an optical network. Nevertheless, the
integration of Ge photodetector into the CMOS process flow is very
challenging due to process complexity and severe temperature
constraints; as
a result, photodetectors fabricated only after completing the
front-end
processes have been previously demonstrated. This talk will
discuss Ge
waveguide photodetectors that have been integrated into the
front-end before
the activation of CMOS well implants. By utilizing a lateral seeded
crystallization method wherein the Ge waveguides are melted during
high-temperature dopant activation, 20$\mu $m-long single-crystal
Ge-on-insulator waveguides were formed. This approach eliminates
the need
for selective epitaxial growth of Ge, and avoids high-density misfit
dislocations formed due to lattice mismatch when growing Ge on Si
substrate.
The photodetectors operate at low applied bias voltages (0.5-1V)
with
bandwidth exceeding 40GHz.
\\[4pt]
[1] W.M.J. Green et al, ``Ultra-compact, low RF power, 10 Gb/s
silicon Mach--Zehnder modulator,'' Opt. Express 15, 17106
(2007).\\[0pt]
[2] Y. A. Vlasov et al, ``High-throughput Silicon Nanophotonic
wavelength-insensitive switch for On-chip Optical Networks,''
Nature Photonics 2, 242 (2008).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.B5.3