US-20260126678-A1 - OPTICAL MODULATORS, METHODS OF MANUFACTURING THE SAME AND APPARATUS INCLUDING OPTICAL MODULATOR

US20260126678A1US 20260126678 A1US20260126678 A1US 20260126678A1US-20260126678-A1

Abstract

An optical modulator may include: a first semiconductor layer; a second semiconductor layer configured as a micro-disk, the second semiconductor layer being on the first semiconductor layer, and the second semiconductor layer including a first doping region and a second doping region, wherein a doping concentration of the first doping region is higher than a doping concentration of the second doping region; a first optical waveguide adjacent to the second semiconductor layer; a first electrode layer on the first doping region; and a second electrode layer on the first doping region and spaced apart from the first electrode layer, wherein the second semiconductor layer includes at least one recess, the second semiconductor layer has at least one step difference due to the at least one recess, and each of the first doping region, the second doping region, and the at least one recess includes a circular shape that is concentric with respect to one another.

Inventors

Duhyun LEE
Kak Namkoong
Jaechul Park

Assignees

SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20251024
Priority Date: 20241105

Claims (20)

1 . An optical modulator comprising: a first semiconductor layer; a second semiconductor layer configured as a micro-disk, the second semiconductor layer being on the first semiconductor layer, and the second semiconductor layer comprising a first doping region and a second doping region, wherein a doping concentration of the first doping region is higher than a doping concentration of the second doping region; a first optical waveguide adjacent to the second semiconductor layer; a first electrode layer on the first doping region; and a second electrode layer on the first doping region and spaced apart from the first electrode layer, wherein the second semiconductor layer comprises at least one recess, wherein the second semiconductor layer has at least one step difference due to the at least one recess, and wherein each of the first doping region, the second doping region, and the at least one recess comprises a circular shape that is concentric with respect to one another.
2 . The optical modulator of claim 1 , wherein the at least one recess of the second semiconductor layer comprises a first recess, a lower surface of the first recess comprises an upper surface of the first doping region and an upper surface of the second doping region, a side surface of the first recess comprises an inner side surface of the second doping region, and a first step difference, of the at least one step difference, is in the second doping region due to the first recess.
3 . The optical modulator of claim 2 , wherein the first doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, the second doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, the lower surface of the first recess comprises an upper surface of the N-doped region of the first doping region, an upper surface of the P-doped region of the first doping region, and a first upper surface of the P-doped region of the second doping region, the side surface of the first recess comprises an inner side surface of the P-doped region of the second doping region, and the first step difference corresponds to a height difference between the first upper surface of the P-doped region of the second doping region and a second upper surface of the second semiconductor layer located higher than the first upper surface.
4 . The optical modulator of claim 2 , wherein the first doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, the second doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, the lower surface of the first recess comprises an upper surface of the N-doped region of the first doping region, an upper surface of the P-doped region of the first doping region, and a first upper surface of the P-doped region of the second doping region, the side surface of the first recess comprises the inner side surface of the P-doped region of the second doping region and an inner side surface of the N-doped region of the second doping region, the first step difference corresponds to a height difference between the first upper surface of the P-doped region of the second doping region and the upper surface of the N-doped region of the second doping region, the N-doped region of the second doping region is between the P-doped region and the first semiconductor layer, and surrounds the P-doped region of the second doping region outside the first recess in a horizontal direction, and an outer side surface of the N-doped region of the second doping region is a side surface of the second semiconductor layer.
5 . The optical modulator of claim 3 , wherein the P-doped region of the first doping region and the N-doped region of the first doping region are concentric, a step difference, of the at least one step difference, exists between a center of the N-doped region of the first doping region, in a horizontal direction, and an edge of the N-doped region of the first doping region, in the horizontal direction, a thickness of the edge of the N-doped region of the first doping region is less than a thickness of the center of the N-doped region of the first doping region, and the P-doped region of the first doping region overlaps with the edge of the N-doped region of the first doping region in a vertical direction, and an upper surface of the P-doped region of the first doping region is coplanar with respect to the upper surface of the N-doped region of the first doping region.
6 . The optical modulator of claim 2 , wherein the at least one recess of the second semiconductor layer is a plurality of recesses comprising the first recess and a second recess inside the first recess, and the second recess is concentric with respect to the first recess, the at least one step difference comprises a plurality of step differences comprising the first step difference and a second step difference, a side surface of the second recess and a lower surface of the second recess comprise surfaces of the first doping region, respectively, the second step difference is inside the first recess due to the second recess, and the first step difference and the second step difference are spaced apart from each other in a horizontal direction parallel to the upper surface of the first semiconductor layer, and a height of the first step difference is different from a height of the second step difference.
7 . The optical modulator of claim 6 , wherein the first doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, each of the N-doped region and the P-doped region comprises a circular shape that is concentric with respect to one another, the lower surface of the second recess comprises an upper surface of the N-doped region, the side surface of the second recess comprises an inner side surface of the P-doped region, and the second step difference corresponds to a height difference between the upper surface of the N-doped region of the first doping region and the upper surface of the P-doped region of the first doping region.
8 . The optical modulator of claim 6 , wherein the first doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, each of the N-doped region and the P-doped region comprises a circular shape that is concentric with respect to one another, the N-doped region and the P-doped region are spaced apart from each other in a vertical direction crossing the upper surface of the first semiconductor layer, the lower surface of the second recess comprises the upper surface of the N-doped region, the side surface of the second recess comprises an inner side surface of the P-doped region, the second step difference corresponds to a height difference between the upper surface of the N-doped region of the first doping region and the upper surface of the P-doped region of the first doping region, a part of the second doping region is between the N-doped region and the P-doped region, the side surface of the second recess comprises an inner side surface of the part of the second doping region and an inner side surface of the P-doped region of the first doping region, the second doping region comprises an N-doped region doped with an N-dopant and a P-doped region doped with a P-dopant, the N-doped region of the second doping region and the P-doped region of the second doping region are concentric, the lower surface of the first recess comprises the upper surface of the P-doped region of the second doping region, and the side surface of the first recess comprises the inner side surface of the P-doped region of the second doping region.
9 . The optical modulator of claim 1 , wherein the at least one recess of the second semiconductor layer comprises a first recess, a lower surface of the first recess comprises an upper surface of the second doping region, a side surface of the first recess comprises a first inner side surface of the second doping region, and a first step difference, of the at least one step difference, is in the second doping region due to the first recess.
10 . The optical modulator of claim 9 , wherein the at least one recess of the second semiconductor layer is a plurality of recesses comprising the first recess and a second recess inside the first recess, and the second recess is concentric with respect to the first recess, the at least one step difference comprises a plurality of step differences comprising the first step difference and a second step difference, a lower surface of the second recess comprises a surface of the first doping region, a side surface of the second recess comprises a second inner side surface of the second doping region, the second step difference is inside the first recess due to the second recess, and the first step difference and the second step difference are spaced apart from each other in a horizontal direction parallel to an upper surface of the first semiconductor layer, and a height of the first step difference is different from a height of the second step difference.
11 . The optical modulator of claim 10 , wherein the first doping region comprises an N-doped region doped with an N-type dopant and a P-doped region doped with a P-type dopant, each of the N-doped region and the P-doped region comprises a circular shape that is concentric with respect to one another, the N-doped region and the P-doped region are spaced apart from each other in a vertical direction crossing the upper surface of the first semiconductor layer, the lower surface of the second recess comprises the upper surface of the N-doped region, the lower surface of the first recess comprises an upper surface of the P-doped region, the side surface of the second recess comprises an inner side surface of the P-doped region, the second step difference corresponds to a height difference between the upper surface of the N-doped region of the first doping region and the lower surface of the first recess, the second doping region comprises an N-doped region doped with an N-dopant and a P-doped region doped with a P-type dopant, each the N-doped region of the second doping region and the P-doped region of the second doping region comprises a circular shape that is concentric with respect to one another, the lower surface of the first recess comprises the upper surface of the P-doped region of the second doping region, and the side surface of the first recess comprises the inner side surface of the P-doped region of the second doping region.
12 . The optical modulator of claim 1 , wherein the at least one recess of the second semiconductor layer comprises a first recess, a side surface of the first recess and a lower surface of the first recess comprise surfaces of the first doping region, respectively, and a first step difference, of the at least one step difference, is in the first doping region due to the first recess.
13 . The optical modulator of claim 12 , wherein the first doping region comprises an N-doped region doped with an N-type dopant, and a P-doped region doped with a P-type dopant, the lower surface of the first recess comprises an upper surface of the N-doped region, the side surface of the first recess comprises an inner side surface of the P-doped region, the N-doped region and the P-doped region overlap in a vertical direction perpendicular to the upper surface of the first semiconductor layer, and are at a side of the first recess in a first horizontal direction, the second doping region surrounds the first doping region in the first horizontal direction and a second horizontal direction that crosses the first horizontal direction, the second doping region comprises an N-doped region doped with an N-type dopant, and a P-doped region doped with a P-type dopant, and the P-doped region of the second doping region is on the N-doped region of the second doping region in the vertical direction.
14 . The optical modulator of claim 1 , wherein the at least one recess of the second semiconductor layer comprises a first recess, a lower surface of the first recess comprises an upper surface of a first-first doped region of the first doping region, a side surface of the first recess comprises an inner side surface of the second doping region and an inner side surface of a first-second doped region of the first doping region, the first-first doped region and the first-second doped region are spaced apart from each other in a vertical direction perpendicular to the upper surface of the first semiconductor layer, the first-first doped region, the first-second doped region, and the first recess are concentric, a step difference, of the at least one step difference, is between an upper surface of the first-first doped region and an upper surface of the first-second doped region due to the first recess, a dopant type of the first-first doped region is opposite of a dopant type of the first-second doped region, an outer diameter of the first-first doped region and an inner diameter of the first-second doped region are equal to each other, and the upper surface of the first-second doped region and the upper surface of the second doping region are coplanar.
15 . The optical modulator of claim 1 , further comprising: a second optical waveguide spaced apart from the second semiconductor layer, wherein the second semiconductor layer is between the first optical waveguide and the second optical waveguide.
16 . A method of manufacturing an optical modulator, the method comprising: forming, on a first semiconductor layer, a second semiconductor layer in a shape of a micro-disk; forming a first doping region in the second semiconductor layer, the first doping region including a circular shape; forming a second doping region in the second semiconductor layer around the first doping region, wherein the second doping region is concentric with the first doping region and surrounds the first doping region in horizontal directions; forming a first step difference in one from among the first doping region and the second doping region; and forming an electrode layer on the first doping region, wherein a doping concentration of the first doping region is higher than a doping concentration of the second doping region.
17 . The method of claim 16 , wherein the first step difference is formed in the first doping region.
18 . The method of claim 17 , further comprising forming a second step difference in the second doping region.
19 . The method of claim 18 , wherein the forming the second doping region comprises: forming a first doping layer; forming a second doping layer on the first doping layer, the second doping layer including the second step difference; and forming a third doping layer on an outer portion of the second step difference of the second doping layer, the third doping layer contacting the first doping layer, wherein a dopant type of the first doping layer is the same as a dopant type of the third doping layer.
20 . An electronic apparatus comprising: a light source; an optical waveguide that is configured to transmit light emitted from the light source; a semiconductor layer adjacent to the optical waveguide, the semiconductor layer configured as a micro-disk; and an amplifier configured to amplify the light transmitted by the optical waveguide, wherein the semiconductor layer comprises a first doping region and a second doping region, wherein the first doping region and the second doping region are at a center of the semiconductor layer in a horizontal direction, wherein the semiconductor layer comprises at least one additional doping region that is outside of the first doping region and the second doping region in the horizontal direction, wherein a dopant type of the first doping region is opposite from a dopant type of the second doping region, wherein a doping concentration of the first doping region and a doping concentration of the second doping region is greater than a doping concentration of the at least one additional doping region, and wherein the semiconductor layer comprises at least one step difference.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application Nos. 10-2024-0155686, filed on Nov. 5, 2024, and 10-2025-0085378, filed on Jun. 26, 2025, in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entireties. BACKGROUND 1. Field The present disclosure relates to an optical device, and more specifically, to an optical modulator of a photonic integrated circuit (PIC), a method of manufacturing the same, and an apparatus including the optical modulator. 2. Description of Related Art In a silicon (Si)-based PIC, a Mach-Zehnder interferometer (MZI) and a micro-ring modulator (MRM) may be used as an optical modulator. For wideband information transmission, technology for increasing the modulation speed of optical modulators, and for parallel processing of signals, wavelength division multiplexing (WDM) technology, in which multiple wavelength signals are simultaneously transmitted through a single waveguide, may be applied. Because an MRM modulates only light with wavelengths that match the resonant wavelength of the micro-ring, it is possible to construct a WDM optical circuit relatively simply, and because high-speed modulation is possible, the MRM may be used. In order to expand the WDM bandwidth, the diameter of the micro-ring may be gradually reduced, but in this process, the curvature of the micro-ring increases, which may result in optical loss. Accordingly, a method of configuring a resonator in the form of a micro-disk as an alternative to a micro-ring has been introduced, but this method may include an element that defines the optical modulation speed. SUMMARY One or more embodiments of the disclosure provide an optical modulator capable of increasing the optical modulation speed. One or more embodiments of the disclosure provide an optical modulator capable of mode filtering. One or more embodiments of the disclosure provide a method of manufacturing the optical modulator. One or more embodiments of the disclosure provide an apparatus including the optical modulator. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the example embodiments of the disclosure. According to an aspect of the disclosure, an optical modulator may include: a first semiconductor layer; a second semiconductor layer configured as a micro-disk, the second semiconductor layer being on the first semiconductor layer, and the second semiconductor layer including a first doping region and a second doping region, wherein a doping concentration of the first doping region is higher than a doping concentration of the second doping region; a first optical waveguide adjacent to the second semiconductor layer; a first electrode layer on the first doping region; and a second electrode layer on the first doping region and spaced apart from the first electrode layer, wherein the second semiconductor layer includes at least one recess, the second semiconductor layer has at least one step difference due to the at least one recess, and each of the first doping region, the second doping region, and the at least one recess includes a circular shape that is concentric with respect to one another. According to an aspect of the disclosure, a method of manufacturing an optical modulator may include: forming, on a first semiconductor layer, a second semiconductor layer in a shape of a micro-disk; forming a first doping region in the second semiconductor layer, the first doping region including a circular shape; forming a second doping region in the second semiconductor layer around the first doping region, wherein the second doping region is concentric with the first doping region and surrounds the first doping region in horizontal directions; forming a first step difference in one from among the first doping region and the second doping region; and forming an electrode layer on the first doping region, wherein a doping concentration of the first doping region is higher than a doping concentration of the second doping region. According to an aspect of the disclosure, an electronic apparatus may include: a light source; an optical waveguide that is configured to transmit light emitted from the light source; a semiconductor layer adjacent to the optical waveguide, the semiconductor layer configured as a micro-disk; and an amplifier configured to amplify the light transmitted by the optical waveguide, wherein the semiconductor layer includes a first doping region and a second doping region, wherein the first doping region and the second doping region are at a center of the semiconductor layer in a horizontal direction, wherein the semiconductor layer includes at least one additional doping region that is outside of the first doping region and the second doping region in the horizontal direction, wher