K. Kazmierski

C‐V measurement and modelization of GaInAs/InP heterointerface with traps

GaInAs/InP heterojunction grown by metalorganic vapor‐phase epitaxy has been studied by C‐V measurements against temperature and frequency. The apparent concentration profiles led to the deduction that both the apparent band discontinuity and the interface charge density are dependent on both the temperature and the frequency. This behavior is explained by assuming a null actual conduction‐band discontinuity and the important presence of traps at the heterojunction. A model of C‐V measurement has been developed in order to account for the presence of traps and the effect of frequency. Simulation results confirm the consistency of the hypothesis of a null actual conduction‐band discontinuity.

The Temperature-Dependent Diffusion Mechanism of Zn in InP Using the Semiclosed Diffusion Method

A novel semiclosed diffusion technique for III-V semiconductors has been developed giving ease of control of the operating and junction depth. The secondary-ion mass-spectrometry atom profiles and carrier-concentration profiles have been used to develop a mechanism involving the temperature dependence of neutral Zn formation. Doubly-ionized interstitials are thought to be the diffusion species.

Very low threshold buried ridge structure lasers emitting at 1.3 μm grown by low pressure metalorganic chemical vapor deposition

GaInAsP‐InP buried ridge structure lasers emitting at 1.3 μm have been fabricated on material grown completely by low pressure metalorganic chemical vapor deposition. These lasers have low threshold (11 mA), exhibit linear (kink‐free) light‐current characteristics up to high powers (10 mW/facets), and can be operated at high temperatures (70 °C). Excellent uniformity over 10 cm2 has been obtained, and an external quantum efficiency of 60% for two faces has been measured.

cw operation of 1.57‐μm GaxIn1−xAsyP1−yInP distributed feedback lasers grown by low‐pressure metalorganic chemical vapor deposition

Continuous wave operation of 1.57‐μm distributed feedback lasers fabricated on material grown by two‐step low‐pressure metalorganic chemical vapor deposition growth process is reported for the first time. Room‐temperature continuous wave threshold currents as low as 60 mA have been measured for devices with cavity length of 300 μm and stripe width of 5 μm. Single longitudinal mode operation at fixed mode was obtained under the continuous wave condition, in the temperature range 9–90 °C, with the wavelength shift of 0.9 A/°C. A stop band of 25 A in which no resonance mode emission existed, was observed in the output spectrum of the distributed feedback laser.

Dark-current and capacitance analysis of InGaAs/InP photodiodes grown by metalorganic chemical vapor deposition

Electron traps have been observed at the InGaAs/InP heterointerface by capacitance voltage measurements in p‐i‐n photodiodes grown by metalorganic chemical vapor deposition. These traps might be responsible for the sharp increase in dark current which occurred when the space‐charge region extended to the InP buffer layer. In addition, the temperature and voltage dependence of dark current has been described using a generation current model which takes into account the thermoionic field emission from an InGaAs midgap trap.

Double Zinc Diffusion Fronts in InP: Correlation with Models of Varying Charge Transfer during Interstitial-Substitutional Interchange

Two concurrent models of interstitial-substitutional interchange involving more than one charge transfer are considered. The assumption of charged vacancy centers is shown to give a model consistent with the experimental data.

High yield manufacture of very low threshold, high reliability, 1.30-µm buried heterostructure laser diodes grown by metal organic chemical vapor deposition

We report the fabrication of very low threshold buried heterostructure lasers by a two-step MOCVD technique. We show very high yield of fabrication, very high uniformity of the initial characteristics, good reproducibility, and low degradation rate during the aging test.

A Simple Model and Calculation of the Influence of Doping and Intrinsic Concentrations on the Interstitial-Substitutional Diffusion Mechanism: Application to Zn and Cd in InP

A simple model of diffusion involving the internal electric field and the presence of neutral effects was developed. The interstitial-substitutional mechanism has been found to be very sensitive to the carrier concentration in the substrate which controls the shape of the diffusion profile and accelerates or retards the diffusion process. The variations of the junction depth with substrate doping has been attributed to the equilibrium shift between interacting species rather than to the internal field. From a detailed analysis of the zinc and cadmium diffusion profiles in InP, the presence of neutrals and the interstitial charge state have been identified.

An Extra Diffusion of Zn into GaAs in Low Concentration Range : Application of the Model of Varying Charge Transfer

A second diffusion of Zn has been observed in GaAs in the low-concentration range. The behaviour is similar to that of double diffusion in InP. The effect of zinc activity in the vapour phase has been studied using a semiclosed-box system. The observed profiles of Zn have been explained using a model of varying charge transfer by vacancy centers during interstitial-substitutional interchanges.

1.55µm BH-DFB lasers grown by LP-MOCVD

We describe in this paper the design and characteristics of buried heterostructure (BH) distributed feedback (DFB) lasers grown by low pressure metalorganic chemical vapor deposition (LP-MOCVD). Typically, threshold current is 30mA for 240µm-long lasers with two cleaved facets and 40mA for lasers with one facet anti-reflection coated. Experimental values are in good agreement with theoretical predictions, based on the laser structure and the coupling coefficient of the diffraction grating. Single longitudinal mode operation is observed for temperatures up to 70°C and output powers up to 6mW. The mode rejection ratio between the DFB mode and the strongest side mode is greater than 30dB.