Tensile strained semiconductor photon emission and detection devices and integrated photonics system

Abstract

Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.

What is claimed is: 
     
         1 . A system in which first circuitry is coupled to spaced apart second circuitry via an optical path, the system comprising a first device which outputs data as electrical output signals to an array of optical emitters, each of the optical emitters having optical output signals modulated with first output signals of driver circuitry that are coupled into a corresponding array of waveguides in which each waveguide of the array of waveguides is in a common optical plane as its corresponding optical emitter, the common optical plane being separated from an underlying substrate by a buried insulating layer, the corresponding array of waveguides providing the optical output signals to a corresponding array of detectors, and the array of detectors providing second output signals to driver circuits which provide a retrieved signal to an electrical bus that distributes signals in the spaced apart second circuitry. 
     
     
         2 . The system of  claim 1 , wherein the underlying substrate is an underlying silicon wafer and each of the optical emitters includes an instance of a strained semiconductor structure that includes a plurality of discrete group IV semiconductor pillars formed in a layer of a group IV semiconductor separated from the underlying silicon wafer by the buried insulating layer and surrounded in a plane parallel to a plane of the layer of the group IV semiconductor by a layer of material that is under tensile in-plane stress such that the pillars are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor so that adjacent ones of the discrete group IV semiconductor pillars share a common underlying group IV semiconductor layer, each respective one of the pillars having a portion of the respective pillar with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor. 
     
     
         3 . The system of  claim 2 , wherein the material that is under tensile in-plane stress is silicon nitride. 
     
     
         4 . The system of  claim 2 , wherein the group IV semiconductor comprises germanium. 
     
     
         5 . The system of  claim 2 , wherein each instance of the strained semiconductor structure further includes an electron emitter material deposited on top of the discrete group IV semiconductor pillars. 
     
     
         6 . The system of  claim 5 , wherein the electron emitter material is n+ doped amorphous germanium. 
     
     
         7 . The system of  claim 5 , wherein the electron emitter material is n+ doped polycrystalline germanium. 
     
     
         8 . The system of  claim 5 , wherein the electron emitter material is n+ doped amorphous silicon. 
     
     
         9 . The system of  claim 5 , wherein the electron emitter material is n+ doped polycrystalline silicon. 
     
     
         10 . The system of  claim 5 , wherein the electron emitter material is n+ doped amorphous silicon germanium. 
     
     
         11 . The system of  claim 5 , wherein the electron emitter material is n+ doped polycrystalline silicon germanium. 
     
     
         12 . The system of  claim 5 , wherein the electron emitter material is a low work function metal. 
     
     
         13 . The system of  claim 5 , wherein the electron emitter material a low work function metal with an interfacial dielectric layer. 
     
     
         14 . The system of  claim 1 , wherein each detector of the array of detectors has biaxially tensile strained group IV semiconductor pillars. 
     
     
         15 . The system of  claim 1 , wherein each detector of the array of detectors includes an instance of a strained semiconductor structure. 
     
     
         16 . The system of  claim 1 , wherein each detector of the array of detectors is in a common optical plane as its corresponding waveguide of the array of waveguides. 
     
     
         17 . The system of  claim 1  wherein the waveguides of the array of waveguides are rib waveguides. 
     
     
         18 . The system of  claim 1 , wherein the optical emitters are each light emitting diodes. 
     
     
         19 . The system of  claim 1 , wherein the first device is a processor. 
     
     
         20 . The system of  claim 1 , wherein the first device is a memory. 
     
     
         21 . The system of  claim 1 , wherein corresponding ones of active regions of each of the optical emitters and detectors are self-aligned with the waveguides and with each other. 
     
     
         22 . The system of  claim 1 , wherein each of the optical emitters is a semiconductor laser diode. 
     
     
         23 . The system of  claim 1 , wherein each of the optical emitters is a light-emitting diode. 
     
     
         24 . The system of  claim 1 , wherein each of the detectors is a photodiode. 
     
     
         25 . A method of communicating data between spaced apart first circuitry and second circuitry via an optical path, the method comprising:
 at the first circuitry, coupling an electrical signal into a first optical device that includes a first semiconductor region configured to generate a responsive optical signal;   transmitting the responsive optical signal through a waveguide; and   at the second circuitry, coupling the responsive optical signal from the waveguide into a second optical device that includes a second semiconductor region,   wherein the waveguide and active regions of the first optical device and the second optical device are self-aligned to one another.   
     
     
         26 . The method of  claim 25 , wherein the waveguide includes an unstrained semiconductor region. 
     
     
         27 . The method of  claim 25 , wherein the first optical device and the second optical device are self-aligned to one another within a common semiconductor arrangement. 
     
     
         28 . The method of  claim 25 , wherein the first and second semiconductor regions each comprise a semiconductor material that is strained locally and selectively such that the semiconductor material becomes optically active with a band structure that corresponds to a band structure of a direct gap semiconductor within a gain medium of the first optical device and the second optical device, respectively. 
     
     
         29 . The method of  claim 25 , wherein the first optical device and the second optical device are formed of a common semiconductor material. 
     
     
         30 . The method of  claim 29 , wherein the common semiconductor material comprises a group IV semiconductor material. 
     
     
         31 . The method of  claim 30 , wherein the group IV semiconductor material comprises germanium and the first semiconductor region includes one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         32 . The method of  claim 30 , wherein the group IV semiconductor material comprises germanium and the second semiconductor region includes one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         33 . The method of  claim 30 , wherein the group IV semiconductor material comprises germanium and each of the first semiconductor region and the second semiconductor region includes one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         34 . The method of  claim 25 , wherein the first semiconductor region and the second semiconductor region are each group IV semiconductor material regions that are surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress. 
     
     
         35 . The method of  claim 34 , wherein the material that is under tensile in-plane stress is silicon nitride. 
     
     
         36 . A system in which first circuitry is coupled to spaced apart second circuitry via a plurality of optical paths, the system comprising a first device which outputs data as a set of parallel electrical output signals to an array of optical emitters, each of the optical emitters including an instance of a semiconductor structure that is configured to generate an optical signal responsive to an input electrical signal, and to transmit the optical signal into a respective waveguide that is optically coupled to a corresponding photodetector, each corresponding photodetector including an instance of a semiconductor structure that is configured to generate an output electrical signal responsive to an input optical signal, and to provide the output electrical signal to a driver circuit that provides a retrieved signal to an electrical bus that distributes signals in the spaced apart second circuitry, wherein active regions of the optical emitters, each respective waveguide, and active regions of each respective photodetector are self-aligned to one another within a common semiconductor arrangement. 
     
     
         37 . The system of  claim 36 , wherein each of the optical emitters and respective photodetectors comprise a semiconductor material that is strained locally and selectively such that the semiconductor material becomes optically active with a band structure that corresponds to a band structure of a direct gap semiconductor within a gain medium of the optical emitter and the photodetector, respectively. 
     
     
         38 . The system of  claim 37 , wherein the semiconductor material comprises a group IV semiconductor material. 
     
     
         39 . The system of  claim 38 , wherein the group IV semiconductor material comprises germanium and the optical emitters each include one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         40 . The system of  claim 38 , wherein the group IV semiconductor material comprises germanium and each respective photodetector includes one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         41 . The system of  claim 38 , wherein the group IV semiconductor material comprises germanium and each of the optical emitters and each respective photodetector includes one or more germanium regions separated from a semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         42 . The system of  claim 38 , wherein each of the optical emitters and each respective photodetector includes group IV semiconductor material regions that are surrounded in a plane parallel to a plane of a layer of group IV semiconductor material by a layer of material that is under tensile in-plane stress. 
     
     
         43 . The system of  claim 42 , wherein the material that is under tensile in-plane stress is silicon nitride. 
     
     
         44 . An optical system comprising an emitter, a waveguide, and a detector, each formed on a common semiconductor substrate, wherein:
 each of the emitter and the detector are made from substantially a same group IV semiconductor material that is strained locally and selectively such that the group IV semiconductor material becomes optically active with a band structure that corresponds to a band structure of a direct gap semiconductor within a gain medium of the emitter and the detector, respectively,   the waveguide is defined, in part, by a low dielectric constant material, and   the waveguide and active regions of the emitter and the detector are self-aligned to one another.   
     
     
         45 . The optical system of  claim 44 , wherein the group IV semiconductor material comprises germanium. 
     
     
         46 . The optical system of  claim 44 , wherein the emitter is a light emitting diode. 
     
     
         47 . The optical system of  claim 44 , wherein the emitter is a laser. 
     
     
         48 . The optical system of  claim 44 , wherein the detector is a photodiode. 
     
     
         49 . The optical system of  claim 44 , wherein the group IV semiconductor material comprises germanium and the emitter includes one or more germanium regions separated from the common semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         50 . The optical system of  claim 44 , wherein the group IV semiconductor material comprises germanium and the detector includes one or more germanium regions separated from the common semiconductor substrate by a buried insulating layer and surrounded in a plane parallel to a plane of a layer of the group IV semiconductor material by a layer of material that is under tensile in-plane stress such that the germanium regions are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor material so that adjacent ones of the germanium regions share a common underlying group IV semiconductor layer, each respective one of the germanium regions having a portion of the respective germanium region with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor material. 
     
     
         51 . A system in which first circuitry within a processor is coupled to second circuitry in a spaced apart or remote portion of the processor via an optical plane, the system comprising:
 an array of light emitting devices, a corresponding array of waveguides, and a corresponding array of photodetectors, each respective light emitting device, waveguide, and photodetector being within the optical plane,   wherein the first circuitry includes driver circuitry that encodes a set of data as parallel electrical output signals, each of the parallel electrical output signals of the driver circuitry modulating an optical output signal of a corresponding one of the light emitting devices, each modulated optical output signal of a light emitting device of the array of light emitting devices being coupled into a respective one the corresponding array of waveguides in the optical plane and each modulated optical output signal of each light emitting device of the array of light emitting devices being transmitted in parallel in the optical plane through the array of waveguides to a respective one of the corresponding array of photodetectors, respective electrical outputs of each of the array of photodetectors being provided to the second circuitry, the second circuitry including driver circuitry that provides retrieved signals from the respective electrical outputs of each of the array of photodetectors to an electrical bus that distributes the retrieved signals within the remote portion of the processor.   
     
     
         52 . The system of  claim 51 , wherein each of the waveguides is a rib waveguide. 
     
     
         53 . The system of  claim 51 , wherein each of the light emitting devices is a semiconductor light emitting diode. 
     
     
         54 . The system of  claim 51 , wherein each of the light emitting devices is a semiconductor laser diode. 
     
     
         55 . The system of  claim 51 , wherein each of the photodetectors is a semiconductor photodiode. 
     
     
         56 . The system of  claim 51 , wherein the light emitting devices and photodetectors each comprise a same semiconductor material. 
     
     
         57 . The optical system of  claim 51 , wherein the light emitting devices and photodetectors each comprise a same group IV semiconductor material. 
     
     
         58 . The system of  claim 51 , wherein the light emitting devices and photodetectors each comprise germanium. 
     
     
         59 . The system of  claim 51 , wherein corresponding ones of active regions of each of the light emitting devices and photodetectors are self-aligned with the waveguides. 
     
     
         60 . The system of  claim 51 , wherein each of the light emitting devices includes an instance of a strained semiconductor structure that includes a plurality of discrete group IV semiconductor pillars formed in a layer of a group IV semiconductor separated from an underlying silicon wafer by a buried insulating layer. 
     
     
         61 . The system of  claim 60 , wherein each of the plurality of discrete group IV semiconductor pillars is surrounded in a plane parallel to a plane of the layer of the group IV semiconductor by a layer of material that is under tensile in-plane stress such that the discrete group IV semiconductor pillars are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor so that adjacent ones of the discrete group IV semiconductor pillars share a common underlying group IV semiconductor layer, each respective one of the discrete group IV semiconductor pillars having a portion of the respective pillar with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor. 
     
     
         62 . The system of  claim 51 , wherein each of the photodetectors includes an instance of a strained semiconductor structure that includes a plurality of discrete group IV semiconductor pillars formed in a layer of a group IV semiconductor separated from an underlying silicon wafer by a buried insulating layer. 
     
     
         63 . The system of  claim 62 , wherein each of the plurality of discrete group IV semiconductor pillars is surrounded in a plane parallel to a plane of the layer of the group IV semiconductor by a layer of material that is under tensile in-plane stress such that the discrete group IV semiconductor pillars are isolated from one another laterally but are not isolated from an underlying portion of the layer of the group IV semiconductor so that adjacent ones of the discrete group IV semiconductor pillars share a common underlying group IV semiconductor layer, each respective one of the discrete group IV semiconductor pillars having a portion of the respective pillar with biaxial tensile strain induced parallel to the plane of the layer of the group IV semiconductor.