Masayoshi Takemi

Zn diffusion in Ruthenium doped InP with annealing by Metalorganic Vapor Phase Epitaxy

Ruthenium (Ru) as the semi-insulated doping material for InP has good characteristics in terms of the capacitance and heat dissipation of the current blocking layer for Laser Diodes. However unintentional Zn diffusion from adjacent p-InP into Ru-InP causes the degradation of Laser characteristics such as the output power. In this paper, we fabricated p-InP/Ru-InP/pInP (p/Ru/p-InP) structure by Metalorganic Vapor Phase Epitaxy (MOVPE) and analyzed the behavior of Zn diffusion from Zn-InP into Ru-InP after annealing by SIMS measurement.

MOCVD regrowth of InP on RIE patterned substrates for p-substrate 1.3 /spl mu/m BH laser application

We have investigated the growth behavior of sulfur-doped n-InP layers around the dry-etched mesas as a function of various H/sub 2/S flow rates. It is found that the growth rate of the n-InP layer of the sidewall of the mesa is significantly affected by the H/sub 2/S flow rate. Consequently the regrown shape of the embedding layer is found to be exactly controlled by the H/sub 2/S flow rate. Using this technique, we have fabricated a p-substrate 1.3/spl mu/m BH laser with a pnp current-blocking structure around the dry-etched mesa and realized excellent lasing characteristics with high reliability for the first time.

Improved selective growth of InP around dry-etched mesas by LP-MOCVD at low growth temperature

We applied a high-speed rotating-disk MOCVD reactor to the selective embedding growth around the mesas formed by reactive ion etching (RIE), and investigated the growth conditions which give planar embedding around the mesas. It is shown that almost planar embedding growth can be achieved even at low growth temperature without introducing any chlorine compounds. Moreover, we discuss the effects of dopants on the behaviors in the selective embedding growth. Special attention has been focused on the growth on the side walls of the nearly-rectangular mesas as well as that near the edges of the masks.

Dependence of the diffusion of zinc from zinc-into ruthenium-doped indium phosphide on zinc concentration

We investigated the Zn concentration dependence of Zn diffusion from Zn-doped InP (Zn-InP) to Ru-doped InP (Ru-InP). As semi-insulated InP, Ru-InP shows advantages in terms of higher resistivity and lower capacitance when Ru-InP is sandwiched by Zn-InP. Control of the diffusion of Zn from the adjacent Zn-InP layer is required to achieve laser diodes with superior characteristics. In this paper, we examined the diffusion of Zn at a Ru-InP stacking structure sandwiched by Zn-InP using metal-organic vapor phase epitaxy.

Anomalous optical characteristics of InGaAsP on GaAs substrates grown by MOVPE

The mechanism of immiscibility of InGaAsP grown by MOVPE has been investigated. Anomalous optical characteristics which are related to the spinodal decomposition are revealed, and growth condition dependence of this phenomenon has been examined in detail.

In-situ monitoring of AlGaInP by reflectance spectroscopy in metalorganic vapor phase epitaxy

We have investigated a real-time reflectance spectroscopy during AlGaInP growth by metalorganic vapor phase epitaxy. The analysis of Fabry-Perot oscillation gives the optical parameters of epitaxial layer such as refractive index (n) and extinction coefficient (k). By using the relationship between these optical parameters and the composition of AlGaInP, in-situ monitoring of growth rate (R/sub g/) and Al content x in (Al/sub x/Ga1-x)/sub 0.51/In/sub 0.49/P is realized without any dependence on the structure. R/sub g/ and Al content x estimated by using this in-situ monitoring method are in good agreement with those obtained by conventional measurement such as thickness, XRD and PL spectroscopy.

120 /spl deg/C operation of 10 Gbps direct modulated 1.3 /spl mu/m AlGaInAs-MQW DFB laser diodes

1.3 /spl mu/m AlGaInAs-MQW ridge waveguide DFB-LDs with a buried grating close to active layer in n-cladding layer was developed. The light output power over 5 mW and clear eye opening with no mask hits for OC-192 under 10 Gbps direct modulation have been realized from 25 /spl deg/C to 120 /spl deg/C. The stable operation over 1600 hours under the APC mode of 10 mW at 95 /spl deg/C has been confirmed.

High speed 1.3 /spl mu/m AlGaInAs DFB-LD with /spl lambda//4-shift grating

1.3 /spl mu/m AlGaInAs DFB-LD with /spl lambda//4-shift grating has been developed for the first time. The light output power over 5 mW at 85/spl deg/C has been obtained for the DFB-LD. Relaxation oscillation frequency (fr) as high as 11.2 GHz@5 mW at a negative detuning of -10 nm has been attained. Clearly opened eye diagram at 10 Gbps modulation has been also confirmed at 75/spl deg/C, which demonstrate excellent transmission characteristics. Stable operation over 1700 hours at 10 mW@85/spl deg/C in the preliminary life test has been confirmed.

Planar selective re-growth around a dry-etched mesa along the [11~0] direction by addition of HCl during MOCVD growth

We have investigated the selective MOCVD re-growth of InP around mesa-stripes along [11¯0] direction formed with reactive ion etching by the addition of HCl gas during MOCVD growth. It is shown that the large overgrowth on the SiO 2 mask in the conventional growth condition is remarkably reduced by the addition of the HCl gas. The mechanism of this effect is analyzed experimentally. It is found that the growth rate on (110) plane (mesa side wall) decreases more remarkably than that on the (001) plane (mesa base) with increasing HCl flow rate. Therefore the growth rate on the side wall can be effectively reduced by the addition of adequate amount of HCl. The reduction of the growth rate on the (110) plane suppress the formation of (111)A plane, which is the cause of the large overgrowth near the mask edge of the mesa stripes. Using these results, we have successfully achieved planar embedded re-growth of InP around dry-etched mesa along [11¯0] direction. This technique is very useful in the application of selective MOCVD growth to the photonic integrated circuits

Selective MOCVD growth of InP around dry-etched mesas with various patterns for photonic integrated circuits

In this paper we have investigated the selective growth of a pnp-InP layer structure as well as the mass-transport effect around dry-etched mesas with various crystallographic directions of stripes. The behavior is found to depend remarkably on the stripe direction. The selective embedding growth around waveguide patterns, such as bifurcations or crossings, is also investigated.