US-12625396-B2 - Optical modulator and method for manufacturing the same

US12625396B2US 12625396 B2US12625396 B2US 12625396B2US-12625396-B2

Abstract

The present disclosure provides an optical modulating structure. The optical modulating structure includes a lower member extending along an insulating layer, a first protrusion over the lower member, and a second protrusion over the lower member and separated from the first protrusion. A first mask layer is formed over the optical modulating structure, wherein the first mask layer covers the second protrusion and a first portion of the lower member between the first protrusion and the second protrusion. A first doping region is formed in an exposed portion of the lower member and at least a portion of an exposed sidewall of the first protrusion. A dielectric layer is formed between the first protrusion and the second protrusion. A method for manufacturing the optical modulating structure is also provided.

Inventors

Wen-Shun Lo
Yingkit Felix Tsui
Jing-Hwang Yang

Assignees

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.

Dates

Publication Date: 20260512
Application Date: 20230510

Claims (20)

1 . A method of manufacturing a semiconductor structure, comprising: receiving a substrate, including a semiconductive material layer over an insulating layer; patterning the semiconductive material layer, thereby defining an optical modulating structure, wherein the optical modulating structure includes a lower member extending along the insulating layer, a first protrusion over the lower member, and a second protrusion over the lower member and separated from the first protrusion; forming a first mask layer over the optical modulating structure, the first mask layer covering the second protrusion and a first portion of the lower member between the first protrusion and the second protrusion; forming a first doping region in an exposed portion of the lower member and at least a portion of an exposed sidewall of the first protrusion, wherein a doping gradient is formed in the first portion of the lower member; and forming a dielectric layer between the first protrusion and the second protrusion.
2 . The method of claim 1 , further comprising: forming a second mask layer over the optical modulating structure and the dielectric layer, the second mask layer exposing at least a portion of the first portion of the lower member and a first portion of the second protrusion adjacent to the first portion of the lower member; and forming a second doping region in the first portion of the second protrusion.
3 . The method of claim 1 , wherein the first doping region is formed by a tilt implantation.
4 . The method of claim 3 , wherein a tilt angle of the tilt implantation is in a range of 5 to 20 degrees.
5 . The method of claim 1 , further comprising: forming a third mask layer over the optical modulating structure and the dielectric layer, the third mask layer exposing the first protrusion; and forming a third doping region in the first protrusion and a second portion of the lower member under the first protrusion, wherein the third doping region overlaps the first doping region in the portion of the exposed sidewall of the first protrusion.
6 . The method of claim 5 , wherein the third doping region has a greater doping concentration in the first protrusion and a lower doping concentration in the second portion of the lower member.
7 . The method of claim 1 , wherein the first doping region is formed by an implantation, and an energy of the implantation is in a range of 5 to 30 kiloelectron-volts (KeV).
8 . The method of claim 1 , wherein the first doping region is formed by an implantation, and a dosage of the implantation is in a range of 1.0E15 to 3.0E15 per square centimeter (cm 2 ).
9 . A method of manufacturing a semiconductor structure, comprising: receiving a substrate, including a semiconductive material layer over an insulating layer; forming a first opening and a second opening in the semiconductive material layer; forming a first photoresist layer over the semiconductive material layer, the first photoresist layer covering the second opening and exposing a portion of a bottom surface of the first opening and a first sidewall of the first opening; performing a first implantation on an exposed portion of the bottom surface of the first opening; and filling the first opening with a dielectric material.
10 . The method of claim 9 , wherein the first implantation is performed with an angle in a range of 0 to 20 degrees.
11 . The method of claim 9 , wherein the first implantation is performed on at least a portion of the first sidewall of the first opening, and results in a doping gradient in a portion of the semiconductive material layer adjacent to a second sidewall opposite to the first sidewall of the first opening.
12 . The method of claim 9 , further comprising: forming a second photoresist layer over the semiconductive material layer, the second photoresist layer exposing a portion of a bottom surface of the second opening and a first sidewall of the second opening; and performing a second implantation on an exposed portion of the bottom surface of the second opening, wherein the second implantation and the first implantation include different types of dopants.
13 . The method of claim 12 , wherein the second implantation is performed on at least a portion of the first sidewall of the second opening, and results in a doping gradient in a portion of the semiconductive material layer adjacent to a second sidewall opposite to the first sidewall of the second opening.
14 . The method of claim 9 , wherein the first opening and the second opening are defined by a hard mask formed over the semiconductive material layer, and the first photoresist layer covers portions of the hard mask.
15 . The method of claim 14 , wherein the hard mask is removed after the formation of the dielectric material.
16 . A semiconductor structure, comprising: a photonic modulator, comprising a first electrode region, a second electrode region and a core region connected by a transition region, wherein the core region is disposed between the first electrode region and the second electrode region; a first dielectric layer, disposed under the photonic modulator; and a second dielectric layer, disposed over the transition region, wherein a first doping concentration of the transition region is greater than a second doping concentration of the second dielectric layer vertically over the transition region by at least a factor of 100, and wherein the transition region includes a third doping concentration less than a fourth doping concentration of the first electrode region, and an overlap portion of the transition region and the first electrode region includes a fifth doping concentration greater than the third doping concentration.
17 . The semiconductor structure of claim 16 , wherein the fifth doping concentration is greater than the fourth doping concentration.
18 . The semiconductor structure of claim 16 , wherein the transition region overlaps the first electrode region by a width in a range of 0.5 to 1.2 microns.
19 . The semiconductor structure of claim 16 , wherein the first doping concentration is in a range of 5.0E19 to 2.0E20 per cm 3 .
20 . The semiconductor structure of claim 19 , wherein the second doping concentration is less than 2.0E18 per cm 3 .

Description

BACKGROUND Semiconductor devices are used in a variety of electronic applications, such as personal computers, cellular phones, digital cameras, and other electronic equipment. The semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon. As the semiconductor industry has progressed into advanced technology process nodes in pursuit of greater device density, issues of current leakage and breakdown voltage of a capacitor have arisen. Optical signals are used for high-speed and secure data transmission between two devices. A device capable of optical data transmission includes at least an integrated circuit having a laser die for transmitting and/or receiving optical signals, and one or more optical components, such as a waveguide for the transmission of the optical signals and a modulator for manipulating a property of the optical signal. As the semiconductor industry has progressed into advanced technology process nodes in pursuit of smaller product scales and greater modulation speeds, various approaches have been studied and an obstacle to improved modulation speeds has been encountered. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIGS. 1 to 18 are schematic cross-sectional diagrams at different stages of a method of manufacturing a semiconductor structure in accordance with some embodiments of the disclosure. FIGS. 19 to 23 are schematic cross-sectional diagrams at different stages of a method of manufacturing a semiconductor structure in accordance with some embodiments of the disclosure. FIG. 24 is a schematic top-view perspective of a photonic modulator in accordance with some embodiments of the disclosure. FIG. 25 is a schematic cross-sectional diagram along a line B-B′ in FIG. 24 at a stage of a method of manufacturing a semiconductor structure. FIG. 26 is a schematic top-view perspective of a photonic modulator in accordance with some embodiments of the disclosure. FIGS. 27 and 28 are flow diagrams of methods of manufacturing a semiconductor structure in accordance with different embodiments of the present disclosure. DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of elements and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “over,” “upper,” “on” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. As used herein, although the terms such as “first,” “second” and “third” describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another. The terms such as “first.” “second” and “third” when used herein do not imply a sequence or order unless clearly indicated by the context. In addition, the term “source/drain region” or “source/drain regions” may refer to a source or a drain, individually or collectively dependent upon the context. Notwithstanding that the numerical ranges and parameters