TY - JOUR
T1 - Native-oxide-confined mid-IR quantum cascade lasers via non-selective oxygen-enhanced wet oxidation
AU - Seibert, Christopher S.
AU - D'Souza, Mithin
AU - Shin, Jae C.
AU - Mawst, Luke J.
AU - Botez, Dan
AU - Hall, Douglas C.
PY - 2009
Y1 - 2009
N2 - In this work, a novel self-aligned process utilizing non-selective, 02-enhanced wet thermal oxidation is presented for fabricating InP-based, ridge waveguide mid-infrared (λ=5.4 μm) quantum cascade lasers (QCLs) with a strain-compensated, 30-stage (1.53 μm thick) InGaAs/AlInAs active region, grown via metal organic chemical vapor deposition. This process, previously used in GaAs-based diode lasers containing low-Al content AlGaAs or even Al-free III-As alloys, forms a highly-insulating native oxide layer while simultaneously smoothing and passivating the etch-exposed active region, resulting in low-loss, strongly-confining waveguides. Here we report the first application of this process for directly oxidizing the deeply-etched QCL InGaAs/AlInAs active region ridge waveguide sidewalls and field (outside the ridge), eliminating the need for a deposited dielectric for electrical isolation, thus allowing self-aligned device fabrication. An 8 hour, 500 °C wet oxidation with 7000 ppm added O2 (relative to N2 carrier gas) yields a uniform oxide of∼350 nm in the field outside the ridge to ∼500 nm on the ridge sidewall. Laser devices tested under room temperature, pulsed excitation exhibit a threshold current density of Jth∼3.2 kA/cm2 for a 19.5 μm wide × 3 mm long stripe width.
AB - In this work, a novel self-aligned process utilizing non-selective, 02-enhanced wet thermal oxidation is presented for fabricating InP-based, ridge waveguide mid-infrared (λ=5.4 μm) quantum cascade lasers (QCLs) with a strain-compensated, 30-stage (1.53 μm thick) InGaAs/AlInAs active region, grown via metal organic chemical vapor deposition. This process, previously used in GaAs-based diode lasers containing low-Al content AlGaAs or even Al-free III-As alloys, forms a highly-insulating native oxide layer while simultaneously smoothing and passivating the etch-exposed active region, resulting in low-loss, strongly-confining waveguides. Here we report the first application of this process for directly oxidizing the deeply-etched QCL InGaAs/AlInAs active region ridge waveguide sidewalls and field (outside the ridge), eliminating the need for a deposited dielectric for electrical isolation, thus allowing self-aligned device fabrication. An 8 hour, 500 °C wet oxidation with 7000 ppm added O2 (relative to N2 carrier gas) yields a uniform oxide of∼350 nm in the field outside the ridge to ∼500 nm on the ridge sidewall. Laser devices tested under room temperature, pulsed excitation exhibit a threshold current density of Jth∼3.2 kA/cm2 for a 19.5 μm wide × 3 mm long stripe width.
KW - Mid-infrared
KW - Nonselective wet oxidation
KW - Quantum cascade laser
KW - Ridge waveguide laser
KW - Strain-compensated
UR - http://www.scopus.com/inward/record.url?scp=63449138704&partnerID=8YFLogxK
U2 - 10.1117/12.809788
DO - 10.1117/12.809788
M3 - Conference article
AN - SCOPUS:63449138704
SN - 0277-786X
VL - 7230
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
M1 - 72301O
T2 - Novel In-Plane Semiconductor Lasers VIII
Y2 - 26 January 2009 through 29 January 2009
ER -