# US 2019/0377205 A1 · Monolithic III-V/Si Waveguide Phase Modulator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0377205 A1 - Document ID: US20190377205A1 - Status: Published application - Kind: A1 - Application number: 16/436,303 - Filed: 2019-06-10 - Published: 2019-12-12 - Earliest claimed: 2018-06-11 - Applicants: Imec Vzw; Katholieke Universiteit Leuven, KU LEUVEN R&D - Inventors: Sanghyeon Kim; Yoojin Ban; Joris Van Campenhout; Maria Ioanna Pantouvaki - Web page: https://patentgrep.com/patent/US20190377205A1 ## CPC - G02F 1/025: in an optical waveguide structure (G02F1/017, {G02F1/2257} take precedence) - H10P 14/276: {Lateral overgrowth} - G02F 1/0151: {modulating the refractive index} - G02F 1/0152: {using free carrier effects, e.g. plasma effect} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract Example embodiments relate to monolithic III-V/Si waveguide phase modulators. One embodiment includes a monolithic integrated phase modulator that includes a waveguide for propagating light. The waveguide for propagating light includes a waveguide base made of a first conductivity type Si-based semiconductor material. The waveguide for propagating light also includes at least one groove formed in a surface of the waveguide base. Further, the waveguide for propagating light includes an epitaxial region formed on the waveguide base in the at least one groove. The epitaxial region is made of a second conductivity type III-V semiconductor material. The waveguide base and the epitaxial region form a monolithically integrated junction diode that is a phase modulation region for light propagated through the waveguide. ## Claims ### Claim 1 A monolithic integrated phase modulator comprising: a waveguide for propagating light, comprising: a waveguide base made of a first conductivity type Si-based semiconductor material; at least one groove formed in a surface of the waveguide base; and an epitaxial region formed on the waveguide base in the at least one groove, wherein the epitaxial region is made of a second conductivity type III-V semiconductor material, and wherein the waveguide base and the epitaxial region form a monolithically integrated junction diode that is a phase modulation region for light propagated through the waveguide. ### Claim 2 (depends on 1) The monolithic integrated phase modulator according to claim 1, wherein the waveguide further comprises: a plurality of grooves formed in the surface of the waveguide base and arranged one after the other along a light propagation direction of the waveguide; and a plurality of epitaxial regions each made of the second conductivity type III-V semiconductor material, wherein epitaxial regions are formed on the waveguide base in each of the plurality of grooves, and wherein the waveguide base and each of the epitaxial regions form the monolithically integrated junction diode. ### Claim 3 (depends on 2) The monolithic integrated phase modulator according to claim 2, wherein each epitaxial region together with the waveguide base is a separate phase modulation region for the light propagated through the waveguide. ### Claim 4 (depends on 2) The monolithic integrated phase modulator according to claim 2, wherein adjacent grooves are distanced by a subwavelength pitch. ### Claim 5 (depends on 2) The monolithic integrated phase modulator according to claim 2, wherein each epitaxial region is arranged to guide at least a part of the light propagated through the waveguide. ### Claim 6 (depends on 2) The monolithic integrated phase modulator according to claim 2, further comprising: a first lead electrically contacting the waveguide base, wherein the first lead is made of the first conductivity type Si-based semiconductor material; and a second lead electrically contacting each epitaxial region, wherein the second lead is made of a second conductivity type Si-based semiconductor material. ### Claim 7 (depends on 6) The monolithic integrated phase modulator according to claim 6, wherein the second lead comprises a sidewall region of the waveguide that electrically contacts each epitaxial region, and wherein the sidewall region of the waveguide of the second lead is made of the second conductivity type Si-based semiconductor material. ### Claim 8 (depends on 7) The monolithic integrated phase modulator according to claim 7, wherein: the epitaxial region has a doping level between 1×1016 cm−3 and 5×1018 cm−3; the first conductivity type Si-based semiconductor material has a doping level between 1×1017 cm−3 and 1×1019 cm−3; or the sidewall region has a doping level between 1×1017 cm−3 and 1×1019 cm−3. ### Claim 9 (depends on 6) The monolithic integrated phase modulator according to claim 6, wherein each epitaxial region and the waveguide base are arranged to be depleted when the junction diode is reversely biased by applying a reverse potential across the first lead and the second lead. ### Claim 10 (depends on 1) The monolithic integrated phase modulator according to claim 1, wherein the at least one groove is a V-groove or a U-groove. ### Claim 11 (depends on 1) The monolithic integrated phase modulator according to claim 1, wherein at least one sidewall of the at least one groove is arranged along a (111)-facet of the waveguide base. ### Claim 12 (depends on 1) The monolithic integrated phase modulator according to claim 1, wherein the epitaxial region has a doping profile that includes a doping level of the second conductivity type that changes in a direction from a surface of the interface between the epitaxial region and the waveguide base to a further surface of the epitaxial region. ### Claim 13 (depends on 12) The monolithic integrated phase modulator according to claim 12, wherein the doping profile comprises: lower doping levels of the second conductivity type near the interface and near the further surface of the epitaxial region; and a higher doping level of the second conductivity type between the lower doping levels. ### Claim 14 A method for producing a monolithic integrated phase modulator, comprising: forming a waveguide for propagating light by: forming a waveguide base from a Si-based semiconductor material; doping the waveguide base to be of a first conductivity type; forming at least one groove in a surface of the waveguide base; and epitaxially growing a region of a second conductivity type III-V semiconductor material on the waveguide base in the at least one groove, wherein the waveguide base and the epitaxially grown region form a monolithically integrated junction diode that is a phase modulation region for light propagated through the waveguide. ### Claim 15 A method of operating a monolithic integrated phase modulator, wherein the monolithic integrated phase modulator comprises: a waveguide for propagating light, comprising: a waveguide base made of a first conductivity type Si-based semiconductor material; at least one groove formed in a surface of the waveguide base; and an epitaxial region formed on the waveguide base in the at least one groove, wherein the epitaxial region is made of a second conductivity type III-V semiconductor material, wherein the waveguide base and the epitaxial region form a monolithically integrated junction diode that is a phase modulation region for light propagated through the waveguide, and wherein the method comprises: propagating light through the waveguide; and reversely biasing the monolithically integrated junction diode to modulate a phase of the light propagated through the waveguide based on a reverse bias potential. ### Claim 16 (depends on 15) The method according to claim 15, wherein the waveguide further comprises: a plurality of grooves formed in the surface of the waveguide base and arranged one after the other along a light propagation direction of the waveguide; and a plurality of epitaxial regions each made of the second conductivity type III-V semiconductor material, wherein epitaxial regions are formed on the waveguide base in each of the plurality of grooves, and wherein the waveguide base and each of the epitaxial regions form the monolithically integrated junction diode. ### Claim 17 (depends on 16) The method according to claim 16, wherein each epitaxial region together with the waveguide base is a separate phase modulation region for the light propagated through the waveguide. ### Claim 18 (depends on 16) The method according to claim 16, wherein adjacent grooves are distanced by a subwavelength pitch. ### Claim 19 (depends on 16) The method according to claim 16, wherein each epitaxial region is arranged to guide at least a part of the light propagated through the waveguide. ### Claim 20 (depends on 16) The method according to claim 16, wherein the monolithic integrated phase modulator further comprises: a first lead electrically contacting the waveguide base, wherein the first lead is made of the first conductivity type Si-based semiconductor material; and a second lead electrically contacting each epitaxial region, wherein the second lead is made of a second conductivity type Si-based semiconductor material.