Semiconductor junction with lateral heterostructure

Abstract

A semiconductor device is introduced which is capable of concentrating electrons and holes into a central volume for enhanced radiative recombination and reduced non-radiative recombination, as well as enhanced optical absorption at longer wavelengths. Carrier confinement is achieved by modifying the material properties of the junction by various means, including but not limited to, strain applied to the interior or exterior region, ion implantation for band-gap engineering or defect introduction, or thermal diffusion.

Description

[0001] SEMICONDUCTOR JUNCTION WITH LATERAL HETEROSTRUCTURE

[0002] Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 667,954 (filed July 5, 2024), which is herein incorporated by reference in its entirety.

[0004] Federally-Sponsored Research and Development

[0005] This invention was made with United States Government support from the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce. The Government has certain rights in this invention.

[0006] Field of Invention

[0007] The present invention relates generally to modification of material properties of semiconductors for enhanced radiative recombination and enhanced optical absorption.

[0008] Background

[0009] In semiconductors, electrons and holes act as charge carriers which enable the flow of electric current. These electrons and holes can be generated by the absorption of photons, and the recombination of electrons and holes may result in the emission of photons. The ability and efficiency of these absorption and recombination processes in semiconductor devices can be a function of the design or structure of the semiconductor device, as well as properties of the semiconductor material. As such, modification of material properties of a semiconductor device is an active field of research.

[0010] Summary of Invention

[0011] A semiconductor device is described herein that concentrates electrons and holes into a central volume for enhanced radiative recombination and reduced non-radiative recombination, as well as enhanced optical absorption at longer wavelengths. Carrier confinement is achieved by modifying the material properties such as the bandgap energy of the junction by various means, including but not limited to, strain applied to the interior or exterior region, ion implantation for band-gap engineering or defect introduction, and / or thermal diffusion.

[0012] The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.

[0013] Brief Description of the Drawings

[0014] FIG. 1 shows, according to some embodiments, an internally-stressed semiconductor device which may operate as a light emitting diode or as a photodiode.

[0015] FIG. 2 shows, according to some embodiments, an additional perspective of the semiconductor device of FIG. 1 .

[0016] FIG. 3 shows, according to some embodiments, a semiconductor device with a doped semiconductor section which may operate as a light emitting diode or as a photodiode.

[0017] FIG. 4 shows, according to some embodiments, an additional perspective of the semiconductor device of FIG. 3.

[0018] FIG. 5 shows, according to some embodiments, a semiconductor device such as the device of FIG. 1 with waveguides in a “north / south” orientation.

[0019] FIG. 6 shows, according to some embodiments, a semiconductor device such as the device of FIG. 1 with waveguides in an “east / west” orientation.

[0020] FIG. 7 shows, according to some embodiments, a semiconductor device with geometry modified to enhance strain in regions of the semiconductor device, such as by partial removal of a supporting layer.

[0021] FIG. 8 shows, according to some embodiments, a scanning-electron micrograph cross-sectional image of a semiconductor device similar to the one showed in FIG. 7.

[0022] FIG. 9 shows, according to some embodiments, a photoluminescence spectrum of an unstrained semiconductor device in (a), and the photoluminescence spectra of several strained semiconductor devices.

[0023] Detailed Description The following description cannot be considered limiting in any way. Various objectives, features, and advantages of the disclosed subject matter can be more fully appreciated with reference to the following detailed description of the disclosed subject matter when considered in connection with the following drawings, in which like reference numerals identify like elements.

[0024] A detailed description of one or more embodiments is presented herein by way of exemplification and not limitation.

[0025] Experiments have been conducted to validate the mechanism of bandgap-tuning by externally induced strain in the silicon. Photoluminescence was observed out to wavelengths beyond 1300 nm in strained silicon, well beyond the typical 1 .13 urn emission usually observed. Narrow-linewidth defects implanted in strained regions showed significant wavelength shifts to their unique photoluminescence signature, further supporting the evidence that significant strain is the cause of the red-shifted emission signature. Numerical simulations of strain have been conducted under realistic parameters, and designs have been made that could be fabricated in a short timeline.

[0026] The disclosed semiconductor device is a unique type of horizontaljunction diode-based device that improves efficiency in the generation and detection of optical photons compared with conventional technology. The semiconductor device can be used for generation of optical photons, and is referred to as a light-emitting diode or LED, or can be used for detecting photons, and is referred to as a photodiode. While some conventional LED or photodiode designs achieve band gap engineering by varying the material composition during growth in the vertical direction, these conventional techniques are limited to applications where the material is grown vertically, typically at high temperature. The semiconductor device described herein can be applied after the emission or absorption medium is left intact to realize lateral heterostructures in a variety of geometries. This lateral confinement of carriers is achieved by confining free carriers in a central region, which limits the deleterious effects of non-radiative recombination that typically plague diodes. The processes for making the semiconductor device can involve to group-IV semiconductors as well as lll-V or ll-VI compound semiconductors. For group IV (Si and Ge in particular), light emission in semiconductors is impeded by the lack of a direct bandgap. Since light emission only proceeds through indirect recombination (assisted by a phonon), the efficiency is low, and the recombination lifetime is too long to be useful for many applications. To overcome this issue, LEDs can incorporate point-type, extended-type defects, or nanocrystals in the material which can exhibit pseudo-direct-gap recombination, which is potentially much more efficient at light emission than indirect-gap recombination. However, this strategy does not provide a solution because it is difficult to confine electrons and holes to the region where light emission is desired. In group lll-V semiconductors, this is achieved by alloy-tuning the materials in a vertical stack to adjust the bandgap, allowing carriers to diffuse into and become trapped in specific areas. Whereas in group IV materials, limitations of epitaxial techniques and lattice-mismatch between available materials prevent this conventional strategy from being used

[0027] Advantageously, the semiconductor device confines electrons or holes to a desired region, wherein such is compatible with group-IV semiconductors and compatible with complementary metal-oxide semiconductor fabrication methods, lowering the cost compared to group Ill-V-based technologies for light emission. The process for making the semiconductor device includes induced strain and localized material composition engineering of the junction area.

[0028] With reference to Figs. 1 and 2, in one embodiment, a semiconductor device (1 ) is disposed on a substrate (2) that may optionally include a thin film of dielectric or semiconductor material (3) separating the device from the substrate. The film (3) provides electrical or optical confinement and isolation from the substrate, can include silicon dioxide, and can have a thickness from 100 nm to 12,000 nm. The device (1 ) includes a p-type-doped section of semiconductor material (4), an n-type-doped section of semiconductor material (5), and an interior region of semiconductor material (6) separating the p-type and n-type sections. Within the interior region (6), there are several instrumental features. The first is a “rib” section of semiconductor material (7), contiguous with the other portions of semiconductor material, that may have a thickness extending from the top surface of (3) which is either the same as, or different from, the thickness of the semiconductor film throughout the rest of the interior region (6). A central section of semiconductor material (8) can be a smaller portion of (7) or can extend throughout the entire rib section (7). In operation of the device as an LED, a voltage Vp is applied to the metal contact (14) on the “p-type” section (4) and a voltage Vn to the metal contact (14) on the “n-type” section (5). When Vp - Vn is sufficiently greater than 0, electrons and holes are injected into the semiconductor medium and will undergo a combination of radiative (photon-emitting) and non- radiative (non-photon-emitting) recombination. In operation of the device as a photodiode, a reverse bias (Vn > Vp) or a bias of zero volts is applied. When photons are absorbed, electron-hole pairs are generated and extracted through the metallic contacts (14), resulting in a photo-current which can be electronically detected. The magnitude of the reverse bias voltage can be chosen to provide avalanche gain (multiplication of generated carriers) when one or more photons are absorbed in the junction.

[0029] In one embodiment, several features confine electrons or holes in the rib section. In an embodiment, with reference to Figs. 1 and 2, a dielectric film (9) has internal stress, e.g., greater than 100 MPa or up to 4 GPa in either tensile or compressive form. Dielectric film 9 is formed (e.g., by deposition) on rib section (7). The dielectric film (9), can include silicon nitride, silicon carbide, silicon oxynitride, silicon dioxide, aluminum oxide, aluminum nitride, silicon oxycarbide, or a combination thereof, or other suitable dielectric materials, or an alternating or a mixed sequence of thinner constituent films, is patterned and etched to limit its extent to an area similar in size to the rib section (7), as shown in the top-view of the device shown in Fig. 2. By positioning and shaping the dielectric film (9), the internal stress in the film induces a degree of mechanical strain inside the semiconductor material of (7). The strain can locally modify the position of the conduction and valence bands in the semiconductor material and reduce the magnitude of the indirect bandgap in the semiconductor material, which results in electrons or holes being confined to the rib section (7). Consequently, the loss of electrons to the p-type doped region (4) and the loss of holes to the n-type doped region (5) is reduced, and the radiative efficiency of the LED increases. In the case of operation as a photodetector, the bandgap reduction experienced in the medium results in a larger optical absorption coefficient at longer wavelengths, for highly efficient and low-noise photodetection in the infrared spectrum. By reducing the magnitude of the indirect bandgap in crystalline silicon, the maximum wavelength is extended for high-performance photodetectors in CMOS- compatible technology.

[0030] In one embodiment, to maintain a long tree-carrier lifetime in the semiconductor medium, the semiconductor can be passivated prior to the deposition of the dielectric film (9). Passivation can be performed by the thermal or plasma-assisted growth of a native oxidized surface, or the deposition of a suitable thin dielectric film.

[0031] In one embodiment, the central region (8) defines the volume in which light emission or absorption will predominantly occur. Regarding the mechanism of light emission or absorption in the central region (8), this may be achieved by various means, including ion implantation of silicon ions, germanium ions, copper ions, carbon ions, noble gases such as argon, krypton, neon, helium, or xenon, or protons.

[0032] In one embodiment, the electronic bandgap of the semiconductor material can be adjusted by other than the strain induced by the optional dielectric film (9) (shown in Figs. 1 and 2). In this embodiment, with reference to Figs 3 and 4, the film (9) is absent, and the rib section (7) is infused with other atomic species that can include germanium or tin. Infusing these atomic species can be by thermal diffusion from a solid source, or by ion implantation.

[0033] In another embodiment, the embodiments described above and as shown in Figs. 1 -4 can be configured such that electron or hole confinement in the rib section (7) can occur by modifying the material properties in the two sections (10). Here, ion implantation or thermal diffusion may be used to either increase the electronic bandgap of the semiconductor material, or to add electrical resistance such that electrons or holes injected into the rib section (7) substantially do not diffuse across the sections (10) into the highly doped regions (4) or (5) where they will not contribute to the radiative emission of light in this device. This can also be achieved with strain-induced band gap broadening. The atomic species that could be incorporated in sections (10) can include carbon, to increase the bandgap, or an atomic species ion-implanted into sections (10) to increase the electrical resistance.

[0034] In another embodiment, if ion implantation is used in central region (8) or rib section (7), it can be followed by an annealing cycle in which the device is raised to an elevated temperature, in the range of 130 Celsius to 1250 Celsius for a time between 10 seconds to 72 hours, depending on the desired effect. The annealing can be done in a vacuum, forming-gas, nitrogen, argon, oxidizing, or any inert atmosphere as required. Optionally, the interior region (6) may also include separate ion-implanted portions (10) which are designed to restrict the diffusion of electrons and holes in the semiconductor medium. The effect of ion implantation may be achieved via the implantation of silicon, germanium, dopants such as boron, arsenic, boron difluoride or phosphorus, noble gases, protons.

[0035] In another embodiment, in reference to Figs. 1 -4, several components of the semiconductor device (1 ) increase the efficiency of light emission or absorption in a group-IV semiconductor lateral junction device. Emitted light is efficiently extracted from the device for operation as an LED. The device delivers photons into an optical waveguide or several optical waveguides disposed on the same substrate (2) although it can extract light in the direction perpendicular to the substrate. Coupling light into optical waveguides includes connection of a dielectric or semiconductor waveguide to various elements of the device. In one embodiment with reference to Fig. 5, waveguides (13) are connected to the interior region (6) on the “north” and “south” ends. Sections (10) are used for electrical isolation to create a gap between the waveguides (13) and the rib section (7). In another embodiment with reference to Fig. 6, waveguides (13) are disposed on the “west” and “east” boundaries of the device (1 ).

[0036] In another embodiment, it is contemplated that waveguides can be disposed in all directions. In some embodiments, waveguides can be disposed on only the “north” and “east” ports, or only one waveguide on the “east” port. The waveguides can include a dielectric or semiconductor material with a refractive index from 1 .4 to 6.0 at the wavelength of operation, or any composite of dielectric or semiconductor materials with refractive indices in that range. The width of the waveguides can be from 100 nm to 5000 nm, and the thickness can be from 10 nm to 4000 nm. It is contemplated that photons may be extracted from the device using the waveguide when the operating the device as a LED, and it is contemplated that photons can be extracted from the waveguide to the device when operating the device as a photodiode.

[0037] In another embodiment, the structure’s cross-sectional composition and geometry can be modified to enhance strain in certain regions of the rib section (7) as exemplified in Fig. 7. Here, the rib section (7) is partially suspended by partial removal of the layer (3) in the vicinity of the device. Rib section (7) can include silicon, and the lower layer (3) can include silicon dioxide. The undercut of (3) can be made by timed application of dilute hydrofluoric acid, which would selectively etch the silicon dioxide but not the silicon. By controlling the time of the etch step, the degree of undercut could be varied as needed. Following this, the surface would then be optionally passivated to minimize surface recombination effects, and then coated with dielectric film (9) to apply strain to the entire structure. Other combinations of materials may also be used, for example, by substituting a different dielectric film in (3) or a different semiconductor in the rib section in (7). The arrangement of Fig. 7 can be used by suspending only a portion of the device’s total length (the direction normal to the page in Fig. 7) and leaving other portions un-suspended, so as to achieve electrical contact through semiconductor portions (4) and (5). Fig. 8 shows a scanning-electron micrograph cross-sectional image of a partially-suspended (or “undercut”) silicon microstructure which was later coated in highly stressed silicon nitride. Here, strain is applied over a smaller structure (the suspended portion) that is not restrained by the mechanically incompliant substrate.

[0038] In one embodiment, the lateral heterojunction device can have an arbitrary geometry, including as an example, extending the length of the junction and connecting the two ends to each other to form an optical resonator. The semiconductor device can also be operated for stimulated light emission in the form of a laser by cavity feedback such as in a ring cavity or by adding mirrors to either end.

[0039] It has been observed that the semiconductor devices of this invention have a reduced bandgap in a semiconductor lateral junction device in the rib section (7) provided by strain applied through a dielectric film, or by alloying of the semiconductor material to locally reduce the bandgap of the semiconductor in the central region. Light-emission-enhancing or absorption-enhancing treatment by ion implantation or diffusion of species can provide in optically active defects in the medium itself. However, adding optically active defects in the central region of the LED or photodiode, without the incorporation of any bandgap-modification step, does not produce the significant benefit of collective free-carrier confinement within the central region of the junction, which provides for maintaining high-efficiency operation as an LED, and for enhancing the absorption of photons in operation as a photodetector. Beneficially, the semiconductor devices of this invention provides carrier-confinement, which is absent in conventional articles.

[0040] Example 1 - Unstressed Structure

[0041] Starting from silicon-on-insulator wafers with “device-layer” or top-layer silicon thicknesses of 60 nm or210 nm, micron-scale (or sub-micron-scale) islands of silicon were patterned and etched on the surface to allow strain to be more easily applied. After etching, the surface was thermally oxidized and then coated with silicon nitride, and then optionally annealed. The structures were cooled to below 30K and illuminated with laser radiation to produce photoluminescence (PL), the wavelength of which can indicate changes in the indirect bandgap or the creation of optically active defects. In Fig. 9 (a), a typical PL spectrum is provided for an unpatterned (uniform, not etched) silicon film, showing free-exciton recombination at 1130 nm, which is characteristic for the material in its natural state.

[0042] Example 2 - Stressed Structures A silicon-on-insulator sample with a device layer thickness of 60 nm was patterned into 1.25 um x 1.25 um square mesa features, acid etched to suspend a portion of silicon as described and shown in Figs. 7 and 8, coated with silicon nitride, and tested to see if the PL spectrum was significantly different from natural unstrained silicon. The measured PL spectrum in this case is shown in Fig. 9(b), showing a broadened and red-shifted peak at approximately 1300 nm. The new PL peak appearing from strained silicon structures could be tuned in strength and red-shifted by adjusting the size, shape and orientation of the silicon.

[0043] In Fig. 9(c), a square mesa 1 .25 um x 1 .25 um in horizontal dimensions on a different thickness of silicon-on-insulator (210 nm) was tested in a similar manner, also having undergone the acid treatment to suspend a portion of the material. A significant shift in peak emission wavelength is observed, now at about 1240 nm, showing that the thickness of silicon can be used to further tune the emission properties.

[0044] Finally, in Fig. 9(d), the same structure is measured without the acid treatment, so that no portion of the silicon is suspended or undercut; in this case, the peak wavelength is closer to 1210 nm.

[0045] Because the emission wavelength in all cases is significantly longer than what is normally observed in silicon and what is observed in the unstressed device of 9(a), we can conclude that the means of applying and using strain on silicon devices is useful for adjusting the bandgap of silicon in strained portions. Furthermore, the additional option to include a suspended semiconductor section, for example by acid treatment or other suitable processing, and later straining said portion by coating it in a film exhibiting substantial stress, offers another means of adjusting strain and concentrating it in certain regions of the semiconductor device. Rib section (7) can be fully suspended over a short length by fully undercutting the isolation layer (3), to the extent that the rib section remains mechanically stable. Lengths from 100 nm to 300 microns can occur for a fully- suspended structure.

[0046] The semiconductor device increases the efficiency and brightness of integrated light sources and photodetectors on CMOS-compatible substrates, wherein the semiconductor device confines free carriers to the region where light emission or absorption can most efficiently occur, and by local modification of the bandgap. The semiconductor device can be made using standard processing techniques available in any CMOS foundry. In terms of technical superiority, the semiconductor device provides brighter light emission for less power consumption than conventional technology and more efficient photodetection at longer wavelengths.

[0047] The semiconductor device has numerous uses, including as an on-chip light sources made from silicon could enable extremely high-bandwidth communications within computer chips built for artificial intelligence processing and acceleration. The semiconductor device can be used in a silicon photodetector at long wavelength, e.g., ~1000 nm, particularly in the O-band from 1260-1360 nm or in an integrated photonic telecommunications article such as a multi-channel receiver or transmitter. The semiconductor device can be used as a light-emitter or photodetector in an Al network.

[0048] Elements of the semiconductor device can be various sizes and can be made of a material that is physically or chemically resilient in an environment in which the semiconductor device is disposed.

[0049] Semiconductor device can be made in various ways. It should be appreciated that semiconductor device includes a number of optical, electrical, or mechanical components, wherein such components can be interconnected and placed in communication (e.g., optical communication, electrical communication, mechanical communication, and the like) by physical, chemical, optical, or free- space interconnects. The components can be disposed on mounts that can be disposed on a bulkhead for alignment or physical compartmentalization. As a result, semiconductor device can be disposed in a terrestrial environment or space environment. Elements of semiconductor device can be formed from silicon, silicon nitride, and the like although other suitable materials, such ceramic, glass, or metal can be used. According to an embodiment, the elements of semiconductor device are formed using 3D printing although the elements of semiconductor device can be formed using other methods, such as injection molding or machining a stock material such as block of material that is subjected to removal of material such as by cutting, laser oblation, and the like. Accordingly, semiconductor device can be made by additive or subtractive manufacturing. In an embodiment, elements of semiconductor device are selectively etched to remove various different materials using different etchants and photolithographic masks and procedures. The various layers thus formed can be subjected to joining by bonding to form semiconductor device.

[0050] While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. Embodiments herein can be used independently or can be combined.

[0051] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The ranges are continuous and thus contain every value and subset thereof in the range. Unless otherwise stated or contextually inapplicable, all percentages, when expressing a quantity, are weight percentages. The suffix (s) as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including at least one of that term (e.g., the colorant(s) includes at least one colorants). Option, optional, or optionally means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not. As used herein, combination is inclusive of blends, mixtures, alloys, reaction products, collection of elements, and the like.

[0052] As used herein, a combination thereof refers to a combination comprising at least one of the named constituents, components, compounds, or elements, optionally together with one or more of the same class of constituents, components, compounds, or elements.

[0053] All references are incorporated herein by reference. The use of the terms “a,” “an,” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. It can further be noted that the terms first, second, primary, secondary, and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. For example, a first current could be termed a second current, and, similarly, a second current could be termed a first current, without departing from the scope of the various described embodiments. The first current and the second current are both currents, but they are not the same condition unless explicitly stated as such.

[0054] The modifier about used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). The conjunction or is used to link objects of a list or alternatives and is not disjunctive; rather the elements can be used separately or can be combined together under appropriate circumstances.

[0055] Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

ClaimsWhat is claimed is:1 . A semiconductor device comprising: a substrate; an isolation layer disposed on at least portions of a first surface of the substrate; a p-type-doped section of semiconductor material disposed on the isolation layer; an n-type-doped section of semiconductor material disposed on the isolation layer; a central section of semiconductor material disposed on the isolation layer; a first rib section of semiconductor material disposed between and contiguous with the p-type-doped section and the central section; and a second rib section of semiconductor material disposed between and contiguous with the n-type-doped section and the central section; wherein the isolation layer comprises a dielectric thin film material or semiconductor material.

2. The semiconductor device of claim 1 , additionally comprising: a dielectric film deposited on the first rib section and the second rib section; wherein the dielectric film is under internal stress and induces a mechanical strain in the first rib section and the second rib section.

3. The semiconductor device of claim 2, wherein the substrate is silicon dioxide and is between 100 nm and 12,000 nm thick.

4. The semiconductor device of claim 2, wherein the dielectric film comprises silicon nitride, silicon carbide, silicon oxynitride, silicon dioxide, aluminum oxide, aluminum nitride, silicon oxycarbide, or any combination of the same.

5. The semiconductor device of claim 4, wherein the dielectric film is under between 100 MPa and 4 GPa of internal stress in tensile or compressive form.

6. The semiconductor device of claim 2, wherein at least some portion of the first rib section and at least some portion of the second rib section is suspended out of contact with the substrate by partial removal of the isolation layer under the first rib section and the second rib section; and wherein the dielectric film is deposited on the first rib section and the second rib section between the first rib section and the substrate and between the second rib section and the substrate.

7. The semiconductor device of claim 1 , wherein the central section has been doped by ion implantation or thermal diffusion.

8. The semiconductor device of claim 7, wherein the central section has been doped by ion implantation of silicon ions, germanium ions, copper ions, carbon ions, noble gases such as argon, krypton, neon, helium, or xenon, or protons.

9. The semiconductor device of claim 1 , wherein the portion of the p- type-doped section proximate to the first rib section and the portion of the n-type- doped section proximate to the second rib section (the proximate sections) have been doped by ion implantation or thermal diffusion.

10. The semiconductor device of claim 9, wherein the proximate sections have been doped with carbon to increase the bandgap in the proximate sections.11 . The semiconductor device of claim 9, wherein the proximate sections have been doped by ion implantation to increase the electrical resistance of the proximate sections.

12. The semiconductor device of claim 1 , additionally comprising an optical waveguide in contact with the central section.

13. The semiconductor device of claim 2, additionally comprising an optical waveguide in contact with the central section.

14. The semiconductor device of claim 1 , wherein the first rib section and the second rib section are doped by thermal diffusion or ion implantation with germanium or tin.

15. A method of using the semiconductor device of claim 2, the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn > 0; wherein radiative recombination occurs in central section; and wherein the proportion of radiative recombination to non-radiative recombination in the central section is greater than an otherwise identical semiconductor device without the dielectric film.

16. A method of using the semiconductor device of claim 10, the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn > 0; wherein radiative recombination occurs in central section; and wherein the proportion of radiative recombination to non-radiative recombination in the central section is greater than an otherwise identical semiconductor device without doped proximate sections.

17. A method of using the semiconductor device of claim 11 , the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn > 0; wherein radiative recombination occurs in central section; andwherein the proportion of radiative recombination to non-radiative recombination in the central section is greater than an otherwise identical semiconductor device without doped proximate sections.

18. A method of using the semiconductor device of claim 14, the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn > 0; wherein radiative recombination occurs in the central section; and wherein the proportion of radiative recombination to non-radiative recombination in the central section is greater than an otherwise identical semiconductor device without the doped first rib section and second rib section.

19. A method of using the semiconductor device of claim 2, the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn <= 0; wherein optical absorption occurs in the central section; and wherein a larger optical absorption coefficient at longer wavelengths in the central section is obtained compared to an otherwise identical semiconductor device without the dielectric film.

20. A method of using the semiconductor device of claim 14, the method comprising: applying a voltage Vp to the p-type-doped section; applying a voltage Vn to the n-type-doped section; wherein Vp-Vn <= 0; wherein optical absorption occurs in the central section; and wherein a larger optical absorption coefficient at longer wavelengths in the central section is obtained compared to an otherwise identical semiconductor device without the doped first rib section and second rib section.

Images