Optoelectronic component with ribbon buried in a semi-insulating structure

Abstract

The invention relates to an optoelectronic component comprising a stack of layers on a substrate in a stacking direction; said stack comprising: a ribbon heterostructure comprising a base and a guide ribbon having a first lateral face and a second lateral face; a first dielectric layer deposited on the first lateral face; a second dielectric layer deposited on the second lateral face; a semi-insulating structure in which the guide ribbon is buried; the first dielectric layer and the second dielectric layer each being confined between the semi-insulating layer and the guide ribbon. Figure for abstract: Fig. 2

Description

Title of the invention: Optoelectronic component with ribbon buried in a semi-insulating structure Scope of application

[0001] The invention relates to the field of active optoelectronic devices with a ribbon buried in a semi-insulating structure. This type of component, which can be a laser, an amplifier, a modulator or a detector, is for example used in the field of telecommunications. Problem raised

[0002] Ridge optoelectronic devices are optical components used in optoelectronic devices such as semiconductor lasers and optical amplifiers. These structures are characterized by a narrow, elongated active region (typically a few micrometers wide and several hundred micrometers long) surrounded by layers of lower refractive index materials. The term "ridge" refers to the shape of the top of the device, which is often shaped like a ridge or ribbon. This shape helps confine light to a small area, which is essential for achieving laser emission from a semiconductor. Ridge optoelectronic devices are typically fabricated using lithography and etching techniques to sculpt the semiconductor layers into a ridge or ribbon shape.Electrodes are then deposited on the ribbon to allow the injection of electric current and the excitation of light in the active region. Ribbon optoelectronic components are widely used in semiconductor optical devices due to their ability to produce narrow, high-quality light beams with high efficiency and low power consumption.

[0003] A more specific development is the semi-insulating buried heterostructure (SIBH) components. [Fig.1a] illustrates a partial view of a state-of-the-art semi-insulating buried heterostructure D0 optoelectronic component. The D0 strip optoelectronic component is produced on a SUB substrate. The substrate may be a bulk substrate made of a type IILV semiconductor material or a stack of several assembled semiconductor materials. The D0 strip optoelectronic component comprises a strip heterostructure comprising an active area 12' confined between an upper confinement structure 13' and a lower confinement structure 11'. The active area 12' is produced by a single layer or a stack of several layers. DO strip optoelectronic component further comprises a first electrode 14' and a second electrode 15' made of electrically conductive layers.

[0004] The ribbon is buried on both sides in the semi-insulating structure 2' along the guiding direction Y. Thus, the buried ribbon structure in a semi-insulating structure consists of a narrow and elongated active region (as in the case of the conventional ribbon structure) which is buried in a layer of semi-insulating material. The semi-insulating material is generally a semiconductor material doped with a metal, for example a III-V semiconductor doped with iron. Doping a semiconductor with a well-defined dose of metal ions makes it possible to modify its energy band structure: the creation of new energy levels in the middle of the band gap which will act as electron traps: the electrons which are captured by these traps and do not participate in the conduction of current and therefore in the electrical pumping of the active zone.The advantage of the buried ribbon structure in a semi-insulator is that it allows better control of the spatial distribution of light and limits parasitic capacitances at the interfaces compared to conventional solutions.

[0005] A first technical problem in components with buried ribbon in a semi-insulating SIBH consists of the diffusion phenomena of the metal dopants (iron ions for example) from the semi-insulating structure to the buried ribbon; and conversely the diffusion of the P dopants from the doped layers of the ribbon to the semi-insulating structure. We thus speak of a phenomenon of inter-diffusion of dopants between the two structures. The phenomenon of inter-diffusion of dopants in this case causes a degradation of the performance of the component for the following reasons: on the one hand a deterioration of the resistivity of the semi-insulating structure and on the other hand an increase in the resistivity of the ribbon, more particularly the P-doped layers. These effects result in a considerable increase in the leakage currents through the lateral diode formed by the P-doped ribbon, the semi-insulating structure and the N-doped base.In addition, the phenomenon of inter-diffusion of dopants causes greater heating of the component by Joule effect which compromises the optimal functioning of the component.

[0006] A second technical problem has been identified concerning the lack of control of the growth of the semiconductor layer by epitaxy during the manufacture of components with ribbon buried in a semi-insulating SIBH. More particularly, the problem is encountered in “components with disoriented ribbon buried in a semi-insulating SIBH” (translation of “tilted semi-insulating buried heterostructure”). In this type of component, the guiding direction defined by the ribbon has a non-zero angle (typically between 5° and 10°) relative to a reference crystallographic direction allowing controlled epitaxial growth depending on the substrate chosen. For example, in the case of growth of an iron-doped InP semi-insulating material from an InP layer, the reference crystallographic direction is the direction given by the Miller indices (011). If the ribbon extends parallel to the reference crystallographic direction, we speak of a ribbon component buried in a SIBH semi-insulator aligned with respect to the crystallographic direction of the substrate.

[0007] In order to understand the second technical problem, [Fig. 1b] illustrates a cross-sectional view of the result of the growth step of the semi-insulating layer for a ribbon component buried in an aligned SIBH semi-insulator. [Fig. 1c] illustrates a cross-sectional view of the result of the growth step of the semi-insulating layer for a disoriented ribbon component buried in a SIBH semi-insulator. In the case of the disoriented ribbon component, the growth dynamics of the semi-insulating layer 2' on either side of the guide ribbon is not controlled because of the difference in growth speed between the different crystallographic planes. Indeed, during the epitaxial growth of the semi-insulating layer 2', an overflow of said semi-insulating layer 2' is observed for the disoriented ribbon component so as to partially, and even completely, cover the upper face of the ribbon.The partial or complete coverage of the upper face of the ribbon by the semi-insulating layer constitutes an obstacle to continuing the following steps of the process because access to this surface is necessary. For example, if the upper surface of the ribbon is covered by the semi-insulating layer 2', it would be impossible to produce a first functional upper electrode 14'.

[0008] To overcome the limitations of existing solutions, the invention proposes a particular structure of an optoelectronic component with a ribbon buried in a semi-insulating layer. The optoelectronic component according to the invention has considerable advantages in terms of improved heat dissipation, electrical insulation and limitation of dopant inter-diffusion phenomena compared to state-of-the-art solutions.

[0009] The invention further relates to a first method for manufacturing a ribbon optoelectronic component buried in a semi-insulator with a single burial layer growth step (translation of One-Step SIBH). The first method makes it possible to solve the problems of undesirable epitaxial overgrowth of the semi-insulating layer previously detailed.

[0010] The invention also relates to a second method for manufacturing a ribbon optoelectronic component buried in a semi-insulator with two stages of burial layer growth (translation of Two-Step SIBH). The second method makes it possible to solve the problems of uncontrolled epitaxial overgrowth of the semi-insulating layer as well as the phenomenon of inter-diffusion of dopants.

[0011] It is emphasized that the first method and the second method are linked together so as to form a single general inventive concept with a view to solving the same technical problem, namely, the uncontrolled growth of the semi-insulating layer which develops in an uncontrolled manner on the upper face of the guide strip as well as the phenomenon of inter-diffusion of dopants.

[0012] Abstract / Claims

[0013] The subject of the invention is an optoelectronic component comprising a stack of layers on a substrate in a stacking direction; said stack comprising: - a ribbon heterostructure comprising a base and a guide ribbon extending in a guide direction orthogonal to the stacking direction, the guide ribbon being configured to propagate a confined light wave; the guide ribbon having a first lateral face and - a second lateral face extending parallel to the stacking direction and to the guide direction; - a first dielectric layer deposited on the first lateral face; - a second dielectric layer deposited on the second lateral face; - a semi-insulating structure in which the guide tape is buried; the first dielectric layer and the second dielectric layer each being confined between the semi-insulating layer and the guide tape.

[0014] According to a particular aspect of the invention, the first dielectric layer and the second dielectric layer are made of a dielectric material incompatible with the deposition of the semi-insulating layer by epitaxy.

[0015] According to a particular aspect of the invention, the first dielectric layer and the second dielectric layer are made of an amorphous dielectric material.

[0016] According to a particular aspect of the invention, the first dielectric layer and the second dielectric layer are made of silicon oxide SiOx or silicon nitride SiNx or silicon oxynitride SiOxNy or amorphous silicon doped with hydrogen aSi:H or an alloy of silicon and silicon nitride or aluminum oxide A12O3.

[0017] According to a particular aspect of the invention, the thickness of the first dielectric layer and the second dielectric layer is greater than or equal to 5 nm.

[0018] According to a particular aspect of the invention, the semi-insulating structure is made of a first semiconductor material doped with metal ions.

[0019] According to a particular aspect of the invention, in a stacking direction, the thickness of the semi-insulating structure is greater than or equal to the thickness of the guide strip.

[0020] According to a particular aspect of the invention, the ribbon heterostructure comprises: • a lower containment structure made of a second semiconductor material; • an active zone made of at least one third semiconductor material; • an upper containment structure made of a fourth semiconductor material; the active zone being confined between the upper confinement structure and the lower confinement structure; said active zone being designed to absorb incident photons or generate photons by recombination of charge carriers injected into the upper and lower confinement structures;

[0021] the guide strip being formed by at least: the upper confinement structure and the active zone.

[0022] The invention also relates to a method for manufacturing an optoelectronic component, comprising the following steps: i. manufacturing an intermediate ribbon by partially etching an initial stack of semiconductor layers deposited on a substrate; said intermediate ribbon being covered by a dielectric etching mask; the intermediate ribbon being arranged on an intermediate base formed by the non-etched layers of said initial stack; said intermediate ribbon extending in a guide direction orthogonal to the stacking direction; ii. manufacturing a first dielectric layer deposited on a first lateral face of the intermediate ribbon and a second dielectric layer deposited on a second lateral face of the intermediate ribbon opposite said first lateral face; iii. manufacturing a guide strip by partial anisotropic etching of the intermediate base, in the stacking direction, on either side of the intermediate strip; the guide strip being arranged on a base formed by the non-etched layers of said initial stack; the guide strip and the base forming a strip heterostructure; said guide strip comprising at least one active zone intended to emit or absorb photons; iv. depositing by epitaxy at least one electrically semi-insulating structure so as to confine at least the active zone in said electrically semi-insulating structure; v. completely removing the dielectric etching mask by etching.

[0023] According to a particular aspect of the invention, the method for manufacturing an optoelectronic component further comprises the following step: i. completely remove the first dielectric layer and the second dielectric layer by etching. Detailed description

[0024] Other characteristics and advantages of the present invention will appear more clearly on reading the description which follows in relation to the following appended drawings.

[0025] [Fig. la] [Fig.la] illustrates a partial view of a state-of-the-art optoelectronic ribbon component. [Fig.la] has already been described.

[0026] [Fig. 1b] [Fig. 1b] illustrates a cross-sectional view of the result of the semi-insulating layer growth step for a buried ribbon component in a SIBH semi-insulator aligned according to the state of the art. [Fig.lb] has already been described.

[0027] [Fig. 1c] [Fig. 1c] illustrates a cross-sectional view of the result of the semi-insulating layer growth step for a disoriented ribbon component buried in a SIBH semi-insulator according to the state of the art. [Fig. 1c] has already been described.

[0028] [Fig.2] [Fig.2] represents a sectional view of an optoelectronic component with buried tape according to the invention.

[0029] [Fig.3a] [Fig.3a] illustrates the first step of the first manufacturing process of the optoelectronic component according to the invention.

[0030] [Fig.3b] [Fig.3b] illustrates the second step of the first manufacturing process of the optoelectronic component according to the invention.

[0031] [Fig.3c] [Fig.3c] illustrates the third step of the first manufacturing process of the optoelectronic component according to the invention.

[0032] [Fig.3d] [Fig.3d] illustrates the fourth step of the first method of manufacturing the optoelectronic component according to the invention.

[0033] [Fig.3e] [Fig.3e] illustrates the fifth step of the first manufacturing process of the optoelectronic component according to the invention.

[0034] [Fig.3f] [Fig.3f] illustrates the sixth step of the first method of manufacturing the optoelectronic component according to the invention.

[0035] [Fig.3g] [Fig.3g] illustrates the seventh step of the first manufacturing process of the optoelectronic component according to the invention.

[0036] [Fig.3h] [Fig.3h] illustrates the eighth step of the first method of manufacturing the optoelectronic component according to the invention.

[0037] [Fig.4] [Fig.4] illustrates a flowchart of the first manufacturing process of the optoelectronic component according to the invention.

[0038] [Fig.5] [Fig.5] illustrates a microscopic cross-sectional view of a component buried ribbon optoelectronic component according to the invention in comparison with a microscopic cross-sectional view of a buried ribbon optoelectronic component according to the state of the art.

[0039] [Fig.6a] [Fig.6a] illustrates the first step of the second method of manufacturing the optoelectronic component according to the invention.

[0040] [Fig.6b] [Fig.6b] illustrates the second step of the second method of manufacturing the optoelectronic component according to the invention.

[0041] [Fig.6c] [Fig.6c] illustrates the third step of the second method of manufacturing the optoelectronic component according to the invention.

[0042] [Fig.6d] [Fig.6d] illustrates the fourth step of the second method of manufacturing the optoelectronic component according to the invention.

[0043] [Fig.6e] [Fig.6e] illustrates the fifth step of the second method of manufacturing the optoelectronic component according to the invention.

[0044] [Fig.6f] [Fig.6f] illustrates the sixth step of the second method of manufacturing the optoelectronic component according to the invention.

[0045] [Fig.6g] [Fig.6g] illustrates the seventh step of the second method of manufacturing the optoelectronic component according to the invention.

[0046] [Fig.6h] [Fig.6h] illustrates the eighth step of the second method of manufacturing the optoelectronic component according to the invention.

[0047] [Fig.7] [Fig.7] illustrates a flowchart of the second manufacturing process of the optoelectronic component according to the invention.

[0048] [Fig.2] represents a sectional view of an optoelectronic component DI according to the invention, making it possible to solve the problems previously described.

[0049] The optoelectronic component DI comprises a stack of layers on a substrate SUB in a stacking direction Z. The substrate SUB is made by a solid wafer of a type IILV semiconductor material alone. Alternatively, the substrate SUB is made by a solid wafer of a type IILV semiconductor material assembled to another substrate made of silicon, or of SOI or of SiO2 deposited on silicon. Alternatively, the substrate SUB is made by a layer of a type IILV semiconductor material deposited on another substrate made of silicon, or of SOI or of SiO2 deposited on silicon. By way of non-limiting example, the type IILV semiconductor material is indium phosphide InP or gallium arsenide GaAs.

[0050] Said stack of layers comprises a ribbon heterostructure 1 for generating and / or guiding an electromagnetic wave, a semi-insulating structure 2 made of a first semiconductor material doped with metal ions, a first electrode 14 and a second electrode 15. The ribbon heterostructure 1 comprises a guide ribbon 12 which extends in a guide direction Y and a base 11 on which the ribbon 12 rests. The guide ribbon 12 is buried in the semi-insulating structure 2. The term “buried” means an arrangement in which the guide ribbon 12 is confined on either side relative to the guide direction Y by the semi-insulating structure 2. The guide strip 12 comprises a first lateral face 12a and a second lateral face 12b which are parallel. The first lateral face 12a forms a plane parallel to the plane formed by the stacking direction Z and to the guiding direction Y. Similarly, the second lateral face 12b forms a plane parallel to the plane formed by the stacking direction Z and to the guiding direction Y.

[0051] The optoelectronic component DI further comprises a first dielectric layer 3a deposited on the first lateral face 12a and a second dielectric layer 3b deposited on the second lateral face 12b. The lower confinement structure 11 is made by a layer 11 of a semiconductor material comprising a protuberance forming part of the guide strip. The lower confinement structure 11 is N-doped. Alternatively, the lower confinement structure 11 may be made by a stack of several N-doped semiconductor layers. Said stack having a base and a protuberance forming part of the guide strip. In the remainder of the description, we will describe the embodiment where the lower confinement structure 11 is made by a layer 11 by way of non-limiting illustration and without excluding a multi-layer lower confinement structure 11.

[0052] The ribbon heterostructure 1 comprises an active area 121 confined between an upper confinement structure 122 and a lower confinement structure 11. The lower confinement structure 11 comprises at least a first layer 11 made of a second semiconductor material. Advantageously, the second semiconductor material is of type III-V, for example InP or GaAs. The second semiconductor material has a first energy gap value Egi. The active area 121, the upper confinement structure 122 and the protuberance of the lower confinement structure 11 together form the guide ribbon 12. The active area 121 is made of a third semiconductor material having a second energy gap value Eg2. Advantageously, the active area 121 is made of a ternary or quaternary alloy of type IILV for example InGaAsP or InGaAlAs.Alternatively, the active zone 121 is produced by a stack of alternating layers of different compositions of ternary or quaternary alloys of type IILV. The thickness of each layer of said stack being from a few nm to around ten nm so as to form a series of quantum wells (translation of the English expression “multi-quantum well layers”).

[0053] The upper confinement structure 122 is made of a fourth semiconductor material having a third energy gap value Eg3. Advantageously, the fourth semiconductor material is identical to the second semiconductor material. This facilitates the epitaxial growth of the ribbon heterostructure. The upper confinement structure 121 is P-doped.

[0054] In the case of an active zone made by a massive layer, the second energy gap value Eg2 of the material constituting the active zone 121 is less than the first energy gap value Egi of the lower confinement structure 11. The second energy gap value Eg2 of the material constituting the active zone 121 is less than the third energy gap value Eg3 of the upper confinement structure 122.

[0055] In the case of an active zone produced by stacking alternating layers, the materials constituting the layers of the alternating stack each have an energy gap value lower than the first energy gap value Egi of the lower confinement structure 11.

[0056] The first electrode 14 is a microstructure made of a conductive material having at least a first portion deposited on the upper surface of the guide strip 12 to create an electrical path between the first electrode 14 and the upper confinement structure 122. The second electrode 15 is a microstructure made of a conductive material electrically connected to the lower confinement structure 11. The first electrode 14 and the second electrode 15 are intended to be connected to an external electrical generator not shown. The application of an electrical voltage between the two electrodes 14 and 15 makes it possible to inject positive charge carriers (holes) into the volume of the upper confinement structure and negative charge carriers (electrons) into the volume of the lower confinement structure. The charge carriers of opposite sign are confined in the active zone 121 with a small gap, to recombine.The recombination of electrons and holes in the active zone 121 allows the emission of photons at a wavelength corresponding to the second energy gap value Eg2. The photons emitted by recombination of injected charge carriers are confined in said layers and form an electromagnetic wave which propagates along the guidance direction Y.

[0057] The semi-insulating structure 2 is made of a semiconductor material doped with a metal, having good thermal conductivity and good electrical insulation. Advantageously, the semi-insulating structure 2 is made of a III-V semiconductor doped with iron, preferably identical to the second semiconductor material to facilitate epitaxy. The first dielectric layer 3a and the second dielectric layer 3b are each confined laterally between the semi-insulating layer 2 and the guide strip 12. The two dielectric layers 3a, 3b make it possible to eliminate the phenomenon of inter-diffusion of dopants between the upper confinement structure 122 and the semi-insulating structure 2. The elimination of the phenomenon of inter-diffusion of the dopants makes it possible to preserve the semi-insulating aspect of the semi-insulating structure 2 and to preserve the conductivity of the upper confinement structure 122. This makes it possible to reduce lateral leakage currents in the optoelectronic component DI and thus improve the overall performance of the component. An additional advantage of inserting the dielectric layers 3a, 3b is the reduction of Joule heating of the component during operation due to the reduction in the resistivity of the upper confinement structure 122.

[0058] Advantageously, the lateral thickness e3 of each of the dielectric separation layers 3a, 3b is greater than or equal to 5 nm so as to ensure good insulation against the diffusion of the dopants.

[0059] As an illustrative and non-limiting example, the two dielectric separation layers 3a, 3b are made of a dielectric material incompatible with the lateral deposition of the semi-insulating layer 2 by epitaxy. This makes it possible to have a controlled process for epitaxial growth of the semi-insulating structure 2, and more particularly to avoid the phenomenon of undesirable overgrowth of the semi-insulating structure 2 described in [Fig. 1e]. The growth incompatibility is determined by at least the following property of the dielectric material of the separation layers 3a, 3b: the chemical reactions between the dielectric used for the separation layers 3a, 3b and the epitaxially grown semi-insulating material 2 do not allow the formation of an adherent layer at the interfaces.

[0060] Advantageously, the first dielectric layer 3a and the second dielectric layer 3b are made of an amorphous dielectric material in order to ensure said growth incompatibility. As an illustrative and non-limiting example, the first dielectric layer 3a and the second dielectric layer 3b are made of silicon oxide SiOx or silicon nitride SiNx or silicon oxynitride SiOxNy or hydrogenated amorphous silicon aSi:H or an alloy of silicon and silicon nitride (called SRN) or aluminum oxide A12O3.

[0061] More advantageously, the first dielectric layer 3a and the second dielectric layer 3b are made of the silicon and silicon nitride alloy SRN which has an intermediate stoichiometry between silicon nitride SiNx and hydrogenated amorphous silicon aSi:H. The silicon and silicon nitride alloy SRN has a modulatable refractive index of between 2 and 3.45 at a wavelength of 1.55 pm. This makes it possible to produce dielectric separation layers 3a, 3b having the advantages previously mentioned without any optical disturbance of the propagation modes in the guide strip and independently of the lateral thickness e3 of the first dielectric layer 3a and the second dielectric layer 3b. It is thus possible with the SRN alloy to increase the thickness in order to ensure better manufacturing control.

[0062] Advantageously, the thickness e2 of the semi-insulating structure 2 is greater than or equal to the thickness el2 of the guide strip 12. This makes it possible to maximize the volume of the semi-insulating structure 2 so as to improve heat dissipation through said semi-insulating structure 2. In state-of-the-art solutions, this maximization is not possible because of the degradation of performance of the component induced by inter-diffusion phenomena.

[0063] Optionally, the upper confinement structure 122 comprises an etch stop layer 124 to protect the active area 121. For example, when the guide strip 12 is formed by indium phosphide InP, the etch stop layer 124 is made by the alloy GalnAsP to allow selective etching of the InP in order to manufacture the hetero ribbon structure 1. For example, when the guide strip 12 is formed by gallium arsenide GaAs, the etch stop layer 124 is made by the alloy GalnP to allow selective etching of the GaAs in order to manufacture the hetero ribbon structure 1. The thickness of the etch stop layer must be less than 20 nm, preferably equal to 10 nm, so as not to cause optical disturbance of the electromagnetic wave guided by the guide strip 12.

[0064] The optoelectronic component DI further comprises an ohmic contact layer 123 confined between the upper surface of the guide strip 12 and the first electrode 14. For example, the ohmic contact layer 123 is made of the fifth P-doped semiconductor material with a dopant concentration greater than that of the upper confinement structure 122.

[0065] Figures 3a to 3h illustrate the steps of a first method PI for manufacturing the optoelectronic component DI according to the invention.

[0066] The first step ia) illustrated by [Fig.3a] consists of providing or manufacturing on the substrate SUB described previously a stack of layers according to the stacking direction Z comprising, starting from said substrate: - a first layer 11' made of an N-doped semiconductor material. - a second layer 121' made of a semiconductor material having an energy gap lower than that of the first layer 11'. The second layer 121' is intended to form the active zone 121. Alternatively, the second layer 121' is replaced by a stack of alternating layers of different compositions of ternary or quaternary alloys of type III-V. The materials constituting the alternating stack layers each have an energy gap value lower than that of the first layer 11'. The alternating stack is intended to form the active zone 121'. In the following, we will describe the embodiment with an active zone made of the second layer 121'. The steps of the method are compatible with an active zone 121 made of a massive layer 121' or a stack of alternating layers. - at least a third layer 122' made of a P-doped semiconductor material. The third layer 122' intended to be part of the upper confinement structure 122. - an electrical contact layer 123' in a P+ doped semiconductor. - a dielectric etching mask 4 defining the area corresponding to the width and length of the guide strip to be manufactured subsequently.

[0067] According to a first example, the first layer 11' is made of N-doped InP with a thickness of 0.5 pm to 5 pm, the second layer 121' is made of a ternary or quaternary alloy of intrinsic Indium with a thickness of 100 nm to 400 nm, the third layer 122' is made of P-doped InP with a thickness of 1 pm to 3 pm, the ohmic contact layer 123' is made of P+-doped InP with a thickness of 100 nm to 300 nm, the etching mask 4 is made of silicon oxide SiOx.

[0068] Step ia) can be carried out by growing thin layers by epitaxy or by sputtering deposition.

[0069] The following step ib), illustrated by [Fig.3b], consists of manufacturing an intermediate ribbon 12i by partially etching the initial stack of semiconductor layers and more particularly the third layer 122' and the electrical contact layer 123'. An intermediate ribbon covered by the dielectric etching mask 4 is obtained. The intermediate ribbon 12i is arranged on an intermediate base formed by the non-etched layers 121', 11' of said initial stack. Said intermediate ribbon extends in a guide direction (Y) orthogonal to the stacking direction (Z). This step is carried out by physical dry etching or wet chemical etching.

[0070] The following step iia), illustrated by [Fig.3c], consists of depositing a dielectric layer 3 over the entire intermediate structure obtained in the previous step. The dielectric layer covers all the external walls of the intermediate structure obtained in the previous step. The thickness of the dielectric layer 3 is greater than or equal to 5nm, in order to take into account potential undesirable etchings in the rest of the process. The material of the dielectric layer 3 is chosen so as to respect the following criteria: - The possibility of selectively etching the dielectric layer 3 with respect to the etching mask 4. - The possibility of selectively etching the mask - relative to the dielectric layer 3. - Advantageously, the incompatibility of the dielectric layer 3 with a subsequent attachment of the epitaxial semi-insulating layer.

[0071] The following step iib), illustrated by [Fig.3d], consists of manufacturing a first dielectric layer 3a deposited on a first lateral face 12a of the intermediate strip 12i and a second dielectric layer 3b deposited on a second lateral face 12b of the intermediate strip 12i opposite said first lateral face 12a. This step is carried out by anisotropic etching without a mask of the dielectric layer 3.

[0072] As non-limiting examples, the following pairs are defined for the choices of materials of the etching mask 4 and the dielectric layer 3: for an etching mask 4 made of silicon oxide SiOx, the dielectric layer 3 is made of silicon nitride SiNx or hydrogenated amorphous silicon aSi:H or an alloy of silicon and silicon nitride SRN. It is possible to selectively etch the materials SiNx, aSi:H and SRN with respect to the silicon oxide SiOx through reactive ion etching processes based on SF6 or XeF2. Following this etching step, the thickness of the dielectric layers 3a, 3b is greater than or equal to 5nm.

[0073] The following step iii), illustrated by [Fig. 3e], consists of manufacturing a guide strip 12 by partial anisotropic etching of the intermediate base, along the stacking direction Z. The etching is carried out on either side of the intermediate strip 12i through the layers 11', 121' and 122. The final shape of the guide strip 12 surmounted by the etching mask 4 is thus obtained.

[0074] The following step iv), illustrated by [Fig.3f], consists of depositing by epitaxy an electrically semi-insulating structure 2 so as to confine the guide strip 12 in said electrically semi-insulating structure 2. The first dielectric layer 3a and the second dielectric layer 3b are each confined between the semi-insulating layer 2 and the guide strip 12. The two separating dielectric layers 3a, 3b are made of a dielectric material incompatible with the lateral deposition of the semi-insulating layer 2 by epitaxy. This makes it possible to have a controlled process for epitaxial growth of the semi-insulating structure 2, and more particularly to avoid the phenomenon of overflow of the semi-insulating structure 2 even for the case of “disoriented strip components buried in a SIBH semi-insulator”. (translation of “tilted semi-insulating buried heterostructure”).The method according to the invention thus makes it possible to overcome the constraint of overflow or unwanted overgrowth of the semi-insulating structure independently of the direction of guidance of the ribbon. This offers a considerable advantage consisting of the possibility of manufacturing components with ribbon buried in a semi-insulator with several directions on the same substrate and with the same manufacturing method. The possibility of manufacturing aligned and disoriented ribbons at the same time with the same quality opens up unexplored possibilities for the design of optoelectronic systems.

[0075] The following step v), illustrated by [Fig.3g], consists of completely removing the dielectric etching mask 4 by selective etching with respect to the separating dielectric layers 3a, 3b. For an etching mask 4 made of silicon oxide SiOx, the dielectric layer 3 is made of silicon nitride SiNx or amorphous silicon doped with hydrogen aSi:H or an alloy of silicon and silicon nitride SRN. It is possible to selectively etch the silicon oxide SiOx with respect to the SiNx, aSi:H and SRN with a buffer solution for oxide etching comprising hydrofluoric acid HF for example.

[0076] The following step vi), illustrated by [Fig.3h], consists of depositing a first electrode 14 and a second electrode 15 as described previously.

[0077] [Fig.4] illustrates a flowchart of the first method of manufacturing the optoelectronic component according to the invention.

[0078] The first step i) consists of providing or manufacturing an intermediate strip 12i by partially etching an initial stack of semiconductor layers deposited on a substrate. Step i) comprises steps ia) and ib) described previously. The second step ii) consists of manufacturing the first dielectric layer 3a deposited on a first lateral face 12a of the intermediate strip and the second dielectric layer 3b deposited on a second lateral face 12b of the intermediate strip 12i opposite said first lateral face 12a. Step ii) comprises steps iia) and iib) described previously. The remaining steps iii) to vi) have been described previously.

[0079] [Fig. 5] illustrates a microscopic cross-sectional view (502) of a buried strip optoelectronic component DI according to the invention in comparison with a microscopic cross-sectional view (501) of a buried strip optoelectronic component D0 according to the state of the art. The phenomenon of undesirable overgrowth of the semi-insulating structure 2 on the guide strip 12 is observed in the disoriented strip component according to the state of the art. In the microscopic cross-sectional view (502) of a component obtained by the method according to the invention, the problem of overflow of the semi-insulating structure 2 on the guide strip 12 has been solved.

[0080] Figures 6a to 6h illustrate the steps of a second method P2 for manufacturing the optoelectronic component D2. The invention also relates to the second method P2 for manufacturing a ribbon optoelectronic component buried in a semi-insulator with two stages of burial layer growth (translation of Two-Step SIBH). The second method P2 makes it possible to solve the problems of overgrowth and uncontrolled epitaxial growth of the semi-insulating layer previously detailed.

[0081] In addition, the problem of inter-diffusion of dopants between the semi-insulating layer and the ribbon is also present in Two-Step SIBH type devices. More particularly, the problem of inter-diffusion is accentuated during the epitaxial growth step of the semi-insulating structure at high temperature (of the order of 700°C). Dopant inter-diffusion phenomena induce an increase in leakage currents in Two-Step SIBH type components in a similar manner to One-step SIBH type components.

[0082] It is emphasized that the first method PI and the second method P2 are linked together so as to form a single general inventive concept with a view to solving the same technical problem, namely, the use of lateral dielectric insulation layers before epitaxial recovery to solve the problem of uncontrolled growth of the semi-insulating layer which develops in an uncontrolled manner on the upper face of the guide strip as well as the problem of interdiffusion of p dopants.

[0083] The first step ia)', illustrated by [Fig.6a], is identical to step ia)' of the first method PL Optionally, the stack shown for the illustration of the second method P2 comprises a layer for the manufacture of diffraction grating 125' (translation of diffraction grating layer) inserted in the third layer 122'.

[0084] The following step ib)' of the second method P2, illustrated by [Fig.6b], is similar to step ib) of the first method PL

[0085] The following step üa)' of the second method P2, illustrated by [Fig.6c], is similar to step iia) of the first method PL

[0086] The following step üb)' of the second method P2, illustrated by [Fig.6d], is similar to step iib) of the first method PL

[0087] The next step üi)' of the second method P2, illustrated by [Fig.6e], is similar to step iii) of the first method PL

[0088] The following step iv)' of the second method P2, illustrated by [Fig.6f], consists of depositing by epitaxy an electrically semi-insulating structure 2 and a diffusion blocking layer 5 so as to confine at least the lower confinement structure 11 and the active zone 121 in the stack formed by the layers 2 and 5. For example, the electrically semi-insulating structure 2 is a semi-insulating layer of iron-doped InP and the diffusion blocking layer 5 is a layer of ruthenium-doped or N-doped InP.

[0089] The following step v)' of the second method P2, illustrated by [Fig.6g], consists of completely removing by etching the first dielectric layer 3a, the second dielectric layer 3b and the etching mask 4. This step can be carried out by two separate selective etching operations or by a non-selective etching operation, typically a chemical etching based on hydrogen fluoride HF.

[0090] The following step vi)' of the second method P2, illustrated by [Fig.6h], consists of growing by epitaxy a cladding layer 6 made of a P-doped semiconductor. The cladding layer 6 encapsulates the visible part of the guide strip 12. Step vi)' further comprises the deposition of an electrical contact layer 123 on the upper surface of the cladding layer 6.

[0091] [Fig.7] illustrates a flowchart of the second manufacturing method P2 according to the invention. The first step i)' consists of providing or manufacturing an intermediate strip 12i by partially etching an initial stack of semiconductor layers deposited on a substrate. Step i)' comprises steps ia)' and ib)' described previously. The second step ii)' consists of manufacturing the first dielectric layer 3a deposited on a first lateral face 12a of the intermediate strip and the second dielectric layer 3b deposited on a second lateral face 12b of the intermediate strip 12i opposite said first lateral face 12a. Step ii)' comprises steps üa)' and üb)' described previously. The remaining steps iii)' to vi)' have been described previously.

Claims

Claims

1. Optoelectronic component (Dl) comprising a stack of layers on a substrate (SUB) in a stacking direction (Z); said stack comprising: - a ribbon heterostructure (1) comprising a base (11) and a guide ribbon (12) extending in a guide direction (Y) orthogonal to the stacking direction (Z), the guide ribbon (12) being configured to propagate a confined light wave; the guide ribbon (12) having a first lateral face (12a) and a second lateral face (12b) extending parallel to the stacking direction (Z) and to the guide direction (Y); - a first dielectric layer (3a) deposited on the first lateral face (12a); - a second dielectric layer (3b) deposited on the second lateral face (12b); - a semi-insulating structure (2) in which the guide ribbon (12) is buried;the first dielectric layer (3a) and the second dielectric layer (3b) each being confined between the semi-insulating layer (2) and the guide strip (12).;

2. Optoelectronic component (Dl) according to claim 1 in which the first dielectric layer (3a) and the second dielectric layer (3b) are made of a dielectric material incompatible with the deposition of the semi-insulating layer (2) by epitaxy.

3. Optoelectronic component (Dl) according to one of claims 1 or 2 wherein the first dielectric layer (3a) and the second dielectric layer (3b) are made of an amorphous dielectric material.

4. Optoelectronic component (Dl) according to one of claims 1 to 3 wherein the first dielectric layer (3a) and the second dielectric layer (3b) are made of silicon oxide SiOx or silicon nitride SiNx or silicon oxynitride SiOxNy or amorphous silicon doped with hydrogen aSi:H or an alloy of silicon and silicon nitride or aluminum oxide A12O3.

5. Optoelectronic component (Dl) according to one of claims 1 to 4 wherein the thickness (e3) of the first dielectric layer (3a) and the second dielectric layer (3b) is greater than or equal to 5nm.

6. Optoelectronic component (Dl) according to one of claims 1 to 5 in which the semi-insulating structure (2) is made of a first semiconductor material doped with metal ions.

7. Optoelectronic component (Dl) according to one of claims 1 to 6 in which, in a stacking direction (Z), the thickness (e2) of the semi-insulating structure (2) is greater than or equal to the thickness (el2) of the guide strip (12).

8. Optoelectronic component (Dl) according to one of claims 1 to 7 wherein the ribbon heterostructure (1) comprises: • a lower confinement structure (11) made of a second semiconductor material; • an active zone (121) made of at least a third semiconductor material; • an upper confinement structure (122) made of a fourth semiconductor material; the active zone being confined between the upper confinement structure (122) and the lower confinement structure (11); said active zone being designed to absorb incident photons or generate photons by recombination of charge carriers injected into the upper (122) and lower (11) confinement structures; the guide ribbon (12) being formed by at least: the upper confinement structure and the active zone (121).

9. A method of manufacturing an optoelectronic component (Dl, D2), comprising the following steps: i. manufacturing an intermediate strip (12i) by partially etching an initial stack of semiconductor layers (11', 121', 122') deposited on a substrate (SUB); said intermediate strip being covered by a dielectric etching mask (4); the intermediate strip (12i) being arranged on an intermediate base formed by the unetched layers of said initial stack (121', 11'); said intermediate strip extending according to a guide direction (Y) orthogonal to the stacking direction (Z); ii. manufacturing a first dielectric layer (3a) deposited on a first lateral face (12a) of the intermediate strip and a second dielectric layer (3b) deposited on a second lateral face (12b) of the intermediate strip (12i) opposite said first lateral face (12a); iii. manufacturing a guide strip (12) by partial anisotropic etching of the intermediate base, in the stacking direction (Z), on either side of the intermediate strip (12i); the guide strip (12) being arranged on a base (11) formed by the non-etched layers of said initial stack; the guide strip (12) and the base (11) forming a heterostructure with strip (1); said guide strip (12) being configured to propagate a confined light wave iv. epitaxially depositing at least one electrically semi-insulating structure (2) so as to confine the guide strip (12) in said electrically semi-insulating structure (2); the first dielectric layer (3a) and the second dielectric layer (3b) each being confined between the semi-insulating layer (2) and the guide strip (12); v. completely remove the dielectric etching mask (4) by etching.

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