Yasutaka Sakata

Surface migration effect and lateral vapor-phase diffusion effect for InGaAsP/InP narrow-stripe selective metal-organic vapor-phase epitaxy

Migration from a masked region and lateral vapor-phase diffusion are the mechanisms of growth-rate enhancement and compositional change for InGaAsP/InP selective metal-organic vapor-phase epitaxy (MOVPE). A novel threshold mask width where the lateral vapor-phase diffusion starts to occur is proposed. When the mask width is less than the threshold mask width, the major mechanism of selective MOVPE is the surface migration from the dielectric mask region, and the lateral vapor-phase diffusion is very small. On the other hand, when the mask width is larger than the threshold mask width, the major mechanism of selective MOVPE switches to lateral vapor-phase diffusion. We discuss the effective migration length on a dielectric mask and the mechanism of the narrow-stripe selective MOVPE for several growth conditions by considering the concept of the threshold mask width.

Low threshold and high uniformity for novel 1.3-/spl mu/m-strained InGaAsP MQW DC-PBH LDs fabricated by the all-selective MOVPE technique

1.3-/spl mu/m-strained InGaAsP multiquantum-well (MQW) double-channel planar buried heterostructure laser diodes (DC-PBH-LDs) were fabricated by all-selective metalorganic vapor phase epitaxy (MOVPE). In the fabrication process, the strained MQW active layer and current-blocking structures were directly formed by selective MOVPE without a semiconductor etching process. A low-threshold current (I/sub th/=2.6 mA@25/spl deg/C for 200-/spl mu/m-long 70%-90% facets) and excellent high-temperature operation (T/sub 0/=84 K, 25/spl deg/C-60/spl deg/C and T/sub 0/=70 K, 25/spl deg/C-85/spl deg/C) were achieved. Furthermore, extremely uniform threshold current and slope efficiency were observed, The median time to failure for these LDs was estimated to be more than 100000 h under the 85/spl deg/C-5 mW aging condition.

All selective MOVPE grown BH-LDs fabricated by the novel self-alignment process

1.3 /spl mu/m-strained MQW BH LDs with a current blocking structure have been developed by selective MOVPE and a newly developed self-alignment process; we call these devices ASM (all selective MOVPE grown)-BH-LDs. The fabrication process, which completely eliminates semiconductor etching, is very promising to realize high-performance LDs with excellent uniformity and reproducibility. The light output power was remarkably improved by a factor of two, compared with previous selective MOVPE-LDs.

All-selective MOVPE-grown 1.3-/spl mu/m strained multi-quantum-well buried-heterostructure laser diodes

Strained InGaAsP multi-quantum-well (MQW) double-channel planar-buried-hetero (DC-PBH) laser diodes (LDs) were fabricated by selective metalorganic-vapor-phase epitaxy (MOVPE). In the laser fabrication process, both the strained MQW active layer and current blocking structure were directly formed by selective MOVPE without any semiconductor etching process. The LDs are called all-selective MOVPE-grown BH LDs. The laser fabrication process can achieve both a precisely controlled gain waveguide structure and an excellent current blocking configuration, realizing the optimized DC-PBH structure. These aspects are essential to the high-performance and low-cost LD, which is strongly demanded for optical access network systems or fiber-to-the-home networks. This paper will show the excellent high-temperature characteristics for 1.3-/spl mu/m Fabry-Perot LDs which have a record threshold current of 18 mA with a low-operation current of 56 mA for 10 mW, and 74 mA for 15 mW at 100/spl deg/C with extremely high uniformity. Furthermore, reliable long-term operation at high temperature (85/spl deg/C) and high-output power of 15 mW has been demonstrated for the first time.

Selective MOVPE growth of InGaAsP and InGaAs using TBA and TBP

Selective metalorganic vapor phase epitaxial (MOVPE) growth of InGaAs(P) using tertiarybutylarsine (TBA) and tertiarybutylphosphine (TBP) was systematically investigated for the first time. Selective growth was successfully achieved and the growth structure was as excellent as the structure using AsH3/PH3. Vapor phase lateral diffusion of group-III species, which is the major mechanism of selective MOVPE, can be easily controlled over the wide range of V/III ratio with using TBA/TBP. From this feature, we propose the selectively grown multiple quantum well waveguide structures which have excellent bandgap controllability by using TBA/TBP.

High-resolution microbeam x-ray diffractometry applied to InGaAsP/InP layers grown by narrow-stripe selective metal-organic vapor phase epitaxy

We measure the diffraction peaks of InGaAsP selective metal-organic vapor-phase epitaxial layers on 1.7-μm-wide InP stripe regions between a pair of SiO2 mask stripes. This is achieved by using an x-ray microbeam with low angular divergence and a narrow energy bandwidth that was produced through two-dimensional condensation of undulator radiation x rays from a synchrotron light source using successive asymmetric diffraction. The lattice strain is investigated by changing the SiO2 mask width from 4 to 40 μm. The rocking curves reveal clear peak shifts in the InGaAsP layers from the higher angle side to the lower angle side of the InP substrate peaks as the mask width increases.

Modulator integrated DFB lasers with more than 600-km transmission capability at 2.5 Gb/s

The modulator integrated DFB laser diodes with more than 600-km transmission capability over normal fiber at 2.5 Gb/s, have been reproducibly achieved. The longest transmission length obtained in the experiment is as long as 800 km.

Low-threshold strained multi-quantum well lasers fabricated by selective metalorganic vapor phase epitaxy without a semiconductor etching process

Abstract Strained InGaAsP multi-quantum well (MQW) buried hetero- (BH) laser diodes (LDs) on a p-InP substrate were fabricated by selective metalorganic vapor phase epitaxy (MOVPE). In the laser fabrication process, both the strained MQW active layer and current blocking structure were directly formed by selective MOVPE without a semiconductor etching process. This novel laser fabrication process produces extremely uniform device characteristics that are essential to the deployment of optical subscriber systems. Furthermore, important device design parameters (e.g. the active stripe shape or the leakage current path configuration) are precisely controlled by only the epitaxial growth steps. This highly controllable laser fabrication method results in a very low-threshold current with excellent uniformity ( I th = 1.78 ± 0.19 mA) for 20 consecutive LDs ( L = 200 μ m with 70%–90% coatings).

Low Drive-Current and Wide Temperature Operation of 1.3-μm AlGaInAs-MQW BH-DFB Lasers by Laterally Enhanced Cladding Layer Growth

Low drive-current and extremely wide temperature (from -45 to 105°C) operation were demonstrated in 10-Gb/s directly-modulated 1.3-μm AlGalnAs-MQW BH-DFB lasers with a new DH structure having a p-InP cladding layer grown by a lateral-growth technique.

Strained MQW-BH-LDs and integrated devices fabricated by selective MOVPE

Selective MOVPE growth is one of the best candidates for achieving integrated MQW waveguide devices, such as DFB laser diode (LD)/electro-absorption (EA) modulator integrated light sources, tunable DBR-LD arrays, DFB-LD/Mach-Zehnder modulator integrated devices and so on. This is because the in-plane bandgap of selectively grown MQW structures can be controlled simply by changing the dielectric mask geometry. Furthermore, direct waveguide formation without a semiconductor etching process can be easily achieved by this technique. The result is highly uniform device characteristics. Recently, it has become to be possible to introduce a current blocking structure into a directly formed waveguide structure. As a result, selective MOVPE growth is strongly expected to fabricate LDs for optical subscriber systems that require excellent uniformity and reproducibility form the high performance LDs. In this paper we discuss a selective MOVPE growth technique for integrated MQW devices followed by all selective MOVPE grown strained MQW-BH-LDs and their extremely uniform device characteristics.