LP-MOVPE growth and properties of high Si-doped InGaAs contact layer for quantum cascade laser applications

Abstract

The work presents doping characteristics and properties of high Si−doped InGaAs epilayers lattice−matched to The electron concentration increases linearly with the ratio of gas−phase molar fraction of the dopant to III group sources (IV/III). The highest electron concentrations suitable for InGaAs plasmon−contact lay− ers of QCL was achieved only for disilane. We also observed a slight influence of the ratio of gas−phase molar fraction of V to III group sources (V/III) on the doping efficiency. Structural measurements using high−resolution X−ray diffraction revealed a dis− tinct influence of the doping concentration on InGaAs composition what caused a lattice mismatch in the range of -240¸-780 ppm for the samples doped by silane and disilane. It has to be taken into account during the growth of InGaAs contact layers to avoid internal stresses in QCL epitaxial structures.

Non-destructive characterization of thin layer resonant tunneling diodes

“…The staircase-doped emitter and collector layers were grouped in one layer; though for the purpose of maximizing the fit accuracy, it is possible to keep them separated. Degenerate doping has been known to increase the lattice stress 39 and, therefore, roughen the surface morphology.…”

The Effect of Buffer Types on the In0.82Ga0.18As Epitaxial Layer Grown on an InP (100) Substrate

“…Therefore, an additional buffer layer is a feasible method commonly used to solve the problem of a large lattice mismatch which has always been a serious problem limiting the appliance of semiconductor hererostructures. Many efforts using low-pressure metalorganic chemical vapor deposition [ 10 ], molecular beam epitaxy [ 11 ], or low-pressure metalorganic vapor phase epitaxy [ 12 ] with different types of buffer structures have been made, thus the qualities of InGaAs materials have been effectively evaluated. In previous reports, various buffer structures, which were implemented to reduce the dislocation density, have been explored, including a thick uniform buffer [ 13 ], a compositionally linearly-graded or step-graded buffer [ 14 , 15 , 16 , 17 ], and a digitally graded buffer [ 18 ].…”

Comprehensive growth and characterization study on highly n-doped InGaAs as a contact layer for quantum cascade laser applications

“…In this study, we have applied pulsed growth and doping methods to obtain highly Si doped n-InGaAs epilayers as a contact layer with improved electrical properties and high crystalline quality grown on InP substrate by MOVPE. InGaAs material generally used as the n-contact layer for QCLs due to its narrow bandgap, low thermal resistivity and good ohmic contact properties [10,11]. Another important reason of preferring InGaAs is that, even for lower doping levels, the anomalous dielectric dispersion is achieved compared to InP which improves the laser performance at shorter wavelengths (<10 μm).…”

“…Moreover, the heavy doping of n-InGaAs layer is crucial to suppress the coupling between the fundamental waveguide mode and the high-loss plasmon mode propagating along the metal contact-semiconductor interface. The doping concentration required for decreasing the InGaAs refractive index near the plasma frequency which significantly enhances the confinement factor of the waveguide mode is in the range of 10 19 -10 20 cm -3 [10,12,13].…”

“…However, using SiH 4 , for the InGaAs doping, it is even difficult to reach the level of ∼10 18 cm −3 [16]. However, there are some studies in the literature, using Si 2 H 6 as the Si source, reporting of n-type doping of InGaAs bulk carrier concentration of 10 19 -10 20 cm −3 [10,17,18] but to our best knowledge there is no report of similar study achieving this high doping levels by using SiH 4 as a dopant source.…”