CN112666728B - Electro-optic modulator - Google Patents
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- CN112666728B CN112666728B CN201910978353.1A CN201910978353A CN112666728B CN 112666728 B CN112666728 B CN 112666728B CN 201910978353 A CN201910978353 A CN 201910978353A CN 112666728 B CN112666728 B CN 112666728B
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Abstract
An electro-optic modulator includes a ridge waveguide including a ridge portion and a slab portion; a first doped region and a second doped region are arranged in the ridge waveguide, and the doping types of the first doped region and the second doped region are different; the first doping region comprises a vertical region and a horizontal region which are arranged in the ridge part and extend along the extending direction of the ridge part, and a plurality of vertical regions which are arranged at intervals along the extending direction of the ridge part; the second doped region includes a portion of the ridge portion other than the first doped region, and forms PN junctions including a horizontal direction, a vertical direction, and a vertical direction adjacent to the horizontal region, the vertical region, and the vertical region of the first doped region, respectively. According to the method, the PN junctions in different directions are designed in the ridge waveguide, the range of a depletion region is enlarged, the modulation efficiency is effectively improved, the optical loss is reduced, and the additional parasitic capacitance is not introduced, so that the influence of the additional capacitance on the modulation bandwidth is avoided.
Description
Technical Field
The present application relates to the field of optical device technologies, and in particular, to an electro-optical modulator.
Background
Silicon-based electro-optic modulators are one of the most important active devices in silicon-based optoelectronic chips, and play an extremely important role in high-speed optical communications. Its function is to convert the high-speed changing electrical signal into a high-speed changing optical signal.
In the silicon optical chip with the application scenario above the single wave 25G, the most practical and commonly used technical solution at present is a carrier depletion modulator (Carrier Depletion Modulator) based on a plasma dispersion effect (Plasma dispersion effect), and a phase shift region (phase shift) of the carrier depletion modulator is a ridge waveguide structure, as shown in fig. 1, and includes a ridge portion 11' and a slab portion (slab portion) 12', a P-type doping 13' and an N-type doping 14' formed in the ridge portion 11', and the P-type doping 13' and the N-type doping 14' are adjacent to form a vertical PN junction extending along the extending direction of the ridge portion. The depletion layer of the PN junction of the modulator with the structure is only at the adjacent position of the two P-type doping 13 'and the N-type doping 14', the modulation efficiency of the optical signal propagated in the ridge waveguide is low, and the requirement of high-speed optical communication on the high modulation efficiency of the high-speed optical modulator is difficult to meet.
Disclosure of Invention
It is an object of the present application to provide an electro-optical modulator with higher light modulation efficiency or lower optical loss.
In order to achieve one of the above objects, the present application provides an electro-optical modulator, including a ridge waveguide including a ridge portion and flat plate portions located on both sides of the ridge portion;
a first doping region and a second doping region are arranged in the ridge waveguide, and the doping types of the first doping region and the second doping region are opposite;
the first doping region comprises a vertical region and a horizontal region which are arranged in the ridge part and extend along the extending direction of the ridge part, and a plurality of vertical regions which are arranged at intervals along the extending direction of the ridge part, wherein the vertical regions extend into a flat plate part on one side of the ridge part along the direction perpendicular to the extending direction of the ridge part;
the horizontal region, the vertical region and the vertical region are mutually connected together, the bottoms of the horizontal region and the vertical region are higher than the bottom of the ridge waveguide, and the width of the horizontal region is smaller than the width of the ridge part;
the second doped region includes a portion of the ridge portion other than the first doped region, the second doped region extending into the flat plate portion on the other side opposite the vertical region;
the second doped region is adjacent to the horizontal region, the vertical region and the vertical region of the first doped region to form PN junctions respectively comprising a horizontal direction, a vertical direction and a vertical direction.
As a further improvement of the embodiment, the horizontal region of the first doped region is located at the bottom, middle or top of the vertical region.
As a further improvement of the embodiment, the horizontal region of the first doped region is located on one or both sides of the vertical region.
As a further improvement of the embodiment, the bottoms of the horizontal and vertical regions of the first doped region are at least 50nm higher than the bottom of the ridge waveguide.
As a further improvement of the embodiment, the thickness of the horizontal region of the first doped region is greater than or equal to 30nm.
As a further improvement of the embodiment, the plurality of vertical regions are disposed at equal intervals along the extending direction of the ridge portion.
As a further improvement of the embodiment, the duty ratio of the vertical region is 20% -80%.
As a further improvement of the embodiment, the flat plate part where the vertical region is located is an intrinsic region or a first lightly doped region; the first lightly doped region is the same as the first doped region in doping type.
As a further improvement of the embodiment, the width of the horizontal zone is greater than or equal to the width of the vertical zone.
As a further improvement of the embodiment, the ridge waveguide further includes a first heavily doped region and a second heavily doped region: the first heavily doped region is positioned outside the vertical region of the first doped region and connected with the tail end of the vertical region, the doping type of the first heavily doped region is the same as that of the first doped region, and the doping concentration of the first heavily doped region is higher than that of the first doped region; the second heavily doped region is positioned outside the second doped region and connected with the second doped region, the doping types of the second heavily doped region and the second doped region are the same, and the doping concentration of the second heavily doped region is higher than that of the second doped region; the electro-optic modulator further includes at least two electrodes, the first heavily doped region and the second heavily doped region being electrically connected to the two electrodes, respectively.
As a further improvement of the embodiment, an extension length of the vertical region into the flat plate portion is greater than or equal to 500nm.
As a further improvement of the embodiment, the ridge waveguide further comprises a first intermediate doped region and a second intermediate doped region: the first middle doping region is positioned between the first doping region and the first heavy doping region and connected with the tail end of the vertical region, the doping types of the first middle doping region and the first doping region are the same, and the doping concentration of the first middle doping region is higher than that of the first doping region and lower than that of the first heavy doping region; the second middle doping region is positioned between the second doping region and the second heavily doping region, the doping types of the second middle doping region and the second doping region are the same, and the doping concentration of the second middle doping region is higher than that of the second doping region and lower than that of the second heavily doping region.
As a further improvement of the embodiment, the extension length of the vertical region into the flat plate portion is between 0 and 500nm.
The application also provides another electro-optic modulator, which comprises a ridge waveguide, wherein the ridge waveguide comprises a ridge part and flat plate parts positioned at two sides of the ridge part;
a first doping region and a second doping region are arranged in the ridge waveguide, and the doping types of the first doping region and the second doping region are opposite;
the first doped region comprises a middle doped region which is arranged in the ridge part and extends along the extending direction of the ridge part, and a plurality of vertical doped regions which are arranged at intervals along the extending direction of the ridge part, wherein the vertical doped regions extend into a flat plate part on one side of the ridge part along the direction perpendicular to the extending direction of the ridge part; the vertical doped region is connected with the middle doped region;
the second doped region comprises two side doped regions which are arranged in the ridge part and are respectively positioned at two sides of the middle doped region of the first doped region, and a top doped region positioned above the first doped region and/or a bottom doped region positioned below the first doped region; the two side doped regions are connected through the top doped region and/or the bottom doped region; the second doped region extends into the flat plate part at the other side opposite to the vertical doped region;
the second doped region adjoins the first doped region to form a PN junction including a horizontal direction, a vertical direction and a vertical direction.
As a further improvement of the embodiment, the cross section of the middle doped region of the first doped region is rectangular; or the middle doped region of the first doped region comprises a vertical region and a horizontal region, and the vertical region and the horizontal region are connected.
As a further improvement of the embodiment, the flat plate part where the vertical region is located is an intrinsic region or a first lightly doped region; the first lightly doped region is the same as the first doped region in doping type.
As a further improvement of the embodiment, a width of the side doped region of the second doped region is greater than or equal to 50nm, and a thickness of at least one of the top doped region and the bottom doped region is greater than or equal to 50nm.
The beneficial effects of this application: and a plurality of PN junctions in different directions are designed in the ridge waveguide, so that the range of a depletion region is enlarged, the modulation efficiency is effectively improved, the optical loss is reduced, and the additional parasitic capacitance is not introduced, thereby avoiding the influence of the additional capacitance on the modulation bandwidth.
Drawings
FIG. 1 is a schematic diagram of a doping structure of a conventional ridge waveguide;
FIG. 2 is a schematic diagram of an electro-optic modulator according to embodiment 1 of the present application;
fig. 3 is a schematic diagram of a doping structure of a ridge waveguide according to embodiment 1 of the present application;
FIG. 4 is a schematic view of the cross section A-A of FIG. 3;
FIG. 5 is a schematic view of the longitudinal section B-B of FIG. 3;
FIG. 6 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 2 of the present application;
FIG. 7 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 3 of the present application;
FIG. 8 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 4 of the present application;
FIG. 9 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 5 of the present application;
FIG. 10 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 6 of the present application;
FIG. 11 is a schematic view of section C-C of FIG. 10;
FIG. 12 is a schematic diagram of the doping structure of a ridge waveguide according to embodiment 7 of the present application;
FIG. 13 is a schematic view of section D-D of FIG. 12;
fig. 14 is a schematic view of an electro-optic modulator according to embodiment 8 of the present application.
Detailed Description
The present application will be described in detail with reference to the following detailed description of the embodiments shown in the drawings. However, these embodiments are not intended to limit the present application, and structural, methodological, or functional modifications made by one of ordinary skill in the art based on these embodiments are included within the scope of the present application.
In the various illustrations of the present application, certain dimensions of structures or portions may be exaggerated relative to other structures or portions for convenience of illustration, and thus serve only to illustrate the basic structure of the subject matter of the present application.
In addition, terms such as "upper", "above", "lower", "below", and the like, used herein to denote spatially relative positions are used for convenience of description to describe one element or feature relative to another element or feature as illustrated in the figures. The term spatially relative position may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly. When an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on, connected to, or intervening elements or layers may be present.
Example 1
As shown in fig. 2-5, the electro-optic modulator of this embodiment comprises at least a ridge waveguide 10 and two electrodes 20. The ridge waveguide 10 includes a ridge portion 11 and flat plate portions 12 on both sides of the ridge portion 11. The ridge waveguide 10 is provided with a first doped region 13 and a second doped region 14, in this embodiment, the first doped region 13 is P-type doped, and the second doped region 14 is N-type doped, however, in other embodiments, the first doped region 13 may be N-type doped, and the second doped region 14 may be P-type doped. The first doped region 13 includes a vertical region 132 and a horizontal region 131 provided in the ridge portion 11 and extending in the extending direction (y-axis direction as shown) of the ridge portion 11, and a plurality of vertical regions 133 provided at intervals in the extending direction of the ridge portion 11, the plurality of vertical regions 133 extending into the flat plate portion 12 on one side of the ridge portion 11 in a direction perpendicular to the extending direction of the ridge portion 11 (i.e., x-axis direction as shown). The horizontal region 131 and the vertical region 132 of the first doped region 13 form a middle doped region of the first doped region 13, the bottoms of the horizontal region 131 and the vertical region 132 are higher than the bottom of the ridge waveguide 10, the width of the horizontal region 131 is smaller than the width of the ridge portion 11, and the vertical region 133 may be also referred to as a vertical doped region. The second doped region 14 includes a portion of the ridge portion 11 other than the first doped region 13 and extends into the flat plate portion 12 on the other side opposite to the vertical region 133, and mainly includes two side doped regions disposed on two sides of the middle doped region of the first doped region 13 in the ridge portion 11, and a bottom doped region disposed below the middle doped region. The two side doped regions of the second doped region are connected by either the bottom doped region or the top doped region. The second doped region 14 adjoins the horizontal region 131, the vertical region 132, and the vertical region 133 of the first doped region 13 to form PN junctions including a horizontal direction P1, a vertical direction P2, and a vertical direction P3, respectively. Here, the horizontal region 131 is parallel to the illustrated xy plane, the vertical region 132 is parallel to the illustrated yz plane, and the vertical region 133 is parallel to the illustrated xz plane.
The slab portion 12 of the ridge waveguide 10 further includes a first heavily doped region 16 outside the vertical region 133 of the first doped region 13, and a second heavily doped region 17 outside the second doped region 14. The first heavily doped region 16 is connected to the end of the vertical region 133 of the first doped region 13, and the doping type of the first heavily doped region 16 and the first doped region 13 is the same, and the doping concentration is higher than that of the first doped region 13. The second heavily doped region 17 is connected to the second doped region 14, and the doping type of the second heavily doped region 17 and the second doped region 14 is the same, and the doping concentration is higher than that of the second doped region 14. In this embodiment, the doping concentration of the first doped region 13 and the second doped region 14 is 1×10 17 cm -3 ～9×10 18 cm -3 Within the range; the doping concentration of the first heavily doped region 16 and the second heavily doped region 17 is 5×10 19 cm -3 ～1×10 21 cm -3 Within the range. The first heavily doped region 16 and the second heavily doped region 17 are electrically connected to the two electrodes 20 by way of conductive vias 30, respectively.In operation, an electrical signal is applied through the two electrodes 20, respectively, to bring the first heavily doped region 16 to a lower potential and the second heavily doped region 17 to a higher potential. The first heavily doped region 16 applies a low potential to the first doped region 13 through each vertical region 133 of the first doped region 13, and the second heavily doped region 17 applies a high potential to the second doped region 14 to generate depletion regions at PN junctions in the horizontal direction P1, the vertical direction P2, and the vertical direction P3, so that the effective refractive index of the optical signal propagating in the ridge waveguide is changed, thereby changing the phase of the optical signal and realizing modulation of the optical signal. The optical modulator of the embodiment designs a plurality of PN junctions in different directions in the ridge waveguide, and PN junctions are arranged in the horizontal direction, the vertical direction and the vertical direction, so that the range of a depletion region is enlarged, and the modulation efficiency is effectively improved.
In this embodiment, the bottoms of the horizontal region 131 and the vertical region 132 of the first doped region 13 are higher than the bottom of the ridge waveguide 10, and the width L of the horizontal region 131 is smaller than the width of the ridge 11 and larger than the width of the vertical region 132, and in other embodiments, the width L of the horizontal region 131 may be equal to the width of the vertical region 132, that is, the cross section formed by the horizontal region 131 and the vertical region 132 together is rectangular. That is, the second doped regions 14 on both sides and at the bottom of the first doped region 13 are conducted mutually, so that the electrode 20 connected with the second doped region 14 is only required to be arranged on one side of the ridge portion 11, and is universal to the electrode of the electro-optical modulator designed by a common PN junction, and no extra parasitic capacitance is introduced, so that the modulation bandwidth is prevented from being influenced by the extra capacitance. Although increasing the number of PN junctions affects junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be achieved by designing the appropriate modulation length.
In this embodiment, the bottoms of the horizontal region 131 and the vertical region 132 of the first doped region 13 are higher than the bottom of the ridge waveguide 10 by at least 50nm, i.e., the thickness H1 of the second doped region 14 under the first doped region 13 is at least 50nm, and a PN junction in the horizontal direction P1 is formed with the horizontal region 131 of the first doped region 13, where the thickness H2 of the horizontal region 131 of the first doped region 13 is greater than or equal to 30nm. The second doped regions 14 on both sides of the first doped region 13 are respectively connected to the first doped regionThe vertical region 132 and the vertical region 133 of the domain 13 form PN junctions in the vertical direction P2 and the vertical direction P3. In this embodiment, the horizontal regions 131 of the first doped region 13 are located on both sides of the bottom of the vertical region 132, and form a doped region having a "cross section" with the vertical region 132. The upper and lower surfaces of the horizontal region 131 are adjacent to the second doped region 14, and form two opposite PN junctions in the horizontal direction P1. The vertical regions 132 are also respectively adjacent to the second doped regions 14 on both sides thereof, forming two opposite PN junctions in the vertical direction P2. Each vertical region 133 is also adjacent to the front and rear second doped regions 14, and forms two opposite PN junctions in the vertical direction P3, and a plurality of pairs of opposite PN junctions in the vertical direction P3 are formed at intervals in the extending direction of the ridge portion 11. In this embodiment, the plurality of vertical regions 133 are disposed at equal intervals along the extending direction of the ridge portion 11, and the duty ratio of the vertical regions 133 is 20% to 80%. The plate portion 12 between the vertical regions 133 is an intrinsic region 15, and the extension length of the vertical region extending into the plate portion, i.e. the width D of the intrinsic region 15, is greater than or equal to 500nm, i.e. the distance D between the first heavily doped region 16 and the second doped region 14 is at least 500nm, to minimize optical losses. Of course, in other embodiments, the intrinsic region 15 may be lightly doped, and the first lightly doped region is replaced by a first lightly doped region having the same doping type as the first doped region and a doping concentration of 1×10 16 cm -3 ～1×10 17 cm -3 Within the range.
Example 2
As shown in fig. 6, unlike embodiment 1, the horizontal region of the first doped region is provided only on one side of the bottom of the vertical region, and forms a doped region having an "L" shape in cross section together with the vertical region. The upper and lower surfaces of the horizontal region are also adjacent to the second doped region to form two opposite PN junctions in the horizontal direction. The vertical regions are also respectively adjacent to the second doped regions at two sides of the vertical regions to form two PN junctions facing away from each other in the vertical direction. Each vertical region is also adjacent to the front and rear second doped regions respectively, two opposite PN junctions in the vertical direction are formed, and a plurality of pairs of opposite PN junctions in the vertical direction are formed at intervals in the extending direction of the ridge portion. In this embodiment, the horizontal region is disposed on the right side of the vertical region, and in other embodiments, the horizontal region may be disposed on the left side of the vertical region, and a doped region having an inverted "L" shape in cross section may be formed together with the vertical region.
Example 3
As shown in fig. 7, unlike embodiment 1, the horizontal region 131 of the first doping region 13 in this embodiment is provided only on one side of the middle of the vertical region 132, forming a doping region of a "T" type having a cross section similar to a lateral direction together with the vertical region 132. Likewise, the bottom of the vertical region 132 is at least 50nm higher than the bottom of the ridge waveguide 10, i.e. there is also a second doped region 14 of at least 50nm thickness below the first doped region 13 to turn on the second doped region 14 on both sides of the first doped region 13. The upper and lower surfaces of the horizontal region 131 are also adjacent to the second doped region 14, so as to form two opposite PN junctions in the horizontal direction. The vertical regions 132 are also respectively adjacent to the second doped regions 14 on both sides thereof, forming two opposite vertical PN junctions. Each vertical region 133 is also adjacent to the front and rear second doped regions 14, and forms two opposite vertical PN junctions, and a plurality of opposite vertical PN junctions are formed at intervals in the extending direction of the ridge portion 11. In this embodiment, the horizontal zone 131 is disposed on the left side of the vertical zone 132, and in other embodiments, the horizontal zone 131 may be disposed on the right side or both sides of the vertical zone 132.
Example 4
As shown in fig. 8, unlike embodiment 1, the horizontal region 131 of the first doping region 13 in this embodiment is divided into two parts, one part being provided at the top of the left side of the vertical region 132 and the other part being provided at the bottom of the right side of the vertical region 132, and forms a doping region having a "Z" shape in cross section together with the vertical region 132. The lower surface of the partial horizontal region 131 at the top is adjacent to the second doped region 14 to form a single PN junction in the horizontal direction, and the upper and lower surfaces of the partial horizontal region 131 at the bottom are also adjacent to the second doped region 14 to form two opposite PN junctions in the horizontal direction. The vertical regions 132 are also respectively adjacent to the second doped regions 14 on both sides thereof, forming two opposite vertical PN junctions. Each vertical region 133 is also adjacent to the front and rear second doped regions 14, and forms two opposite vertical PN junctions, and a plurality of opposite vertical PN junctions are formed at intervals in the extending direction of the ridge portion 11.
Of course, in other embodiments, the horizontal regions of the first doped region may be modified differently, and the number thereof is not limited, for example, the horizontal regions may also form a cross shape, a "earth" shape, a "king" shape, a "T" shape, an "E" shape, or the like with the vertical regions.
Example 5
As shown in fig. 9, the electro-optical modulator of this embodiment includes a ridge waveguide 10 and two electrodes, and a first heavily doped region and a second heavily doped region on both sides of the ridge waveguide 10 are electrically connected to the two electrodes, respectively. The ridge waveguide 10 includes a ridge portion 11 and flat plate portions 12 located on both sides of the ridge portion 11. The ridge waveguide 10 is provided with a first doped region 13 and a second doped region 14, where the doping types of the first doped region 13 and the second doped region 14 are opposite, and in this embodiment, the first doped region 13 is P-type doped, and the second doped region 14 is N-type doped, and of course, in other embodiments, the first doped region 13 may be N-type doped, and the second doped region 14 may be P-type doped. The first doped region 13 includes a middle doped region 134 (may include a horizontal region and a vertical region) disposed in the ridge portion 11 and extending along the extending direction of the ridge portion 11 (i.e., the illustrated y-axis direction), and a plurality of vertical doped regions 135 (similar to the vertical regions in the above embodiments) disposed at intervals along the extending direction of the ridge portion 11, wherein the vertical doped regions 135 extend into the flat plate portion 12 on one side of the ridge portion 11 along a direction perpendicular to the extending direction of the ridge portion 11 (i.e., the illustrated x-axis direction), and the vertical doped regions 135 are connected to the middle doped region 134. The second doped region 14 includes two side doped regions 141 disposed in the ridge portion 11 and located on two sides of the middle doped region 134 of the first doped region 13, and a bottom doped region 142 located below the first doped region 13, where the two side doped regions 141 are connected by the bottom doped region 142. The second doped region 14 extends into the plate portion 12 on the other side opposite the vertical doped region 135. The two side doped regions 141 of the second doped region 14 are respectively adjacent to the middle doped region 134 and the vertical doped region 135 of the first doped region 13, forming a PN junction including a vertical direction P2 and a vertical direction P3; the bottom doped region 142 of the second doped region 14 adjoins the middle doped region 134 of the first doped region 13, forming a PN junction in the horizontal direction P1.
As in embodiment 1, the first heavily doped region outside the ridge waveguide is connected to the end of the vertical doped region 135 of the first doped region 13, and the doping type of the first heavily doped region is the same as that of the first doped region 13, and the doping concentration is higher than that of the first doped region 13. The second heavily doped region is connected to the second doped region 14, and the doping type of the second heavily doped region is the same as that of the second doped region 14, and the doping concentration of the second heavily doped region is higher than that of the second doped region 14. When the device works, electric signals are respectively applied through the two electrodes, so that the first heavily doped region is at a lower potential, and the second heavily doped region is at a higher potential. The first heavily doped region applies a low potential to the first doped region 13 through each vertical doped region 135 of the first doped region 13, and the second heavily doped region applies a high potential to the second doped region 14 to generate depletion regions at the PN junctions in the horizontal direction P1, the vertical direction P2 and the vertical direction P3, so that the effective refractive index of the optical signal propagating in the ridge waveguide is changed, thereby changing the phase of the optical signal and realizing modulation of the optical signal. The optical modulator of the embodiment designs a plurality of PN junctions in different directions in the ridge waveguide, and PN junctions are arranged in the horizontal direction, the vertical direction and the vertical direction, so that the range of a depletion region is enlarged, and the modulation efficiency is effectively improved.
In this embodiment, the width d of the side doped 141 region of the second doped region 14 is greater than or equal to 50nm, the thickness h of the bottom doped region 142 is greater than or equal to 50nm, and the two side doped regions 141 are connected by the bottom doped region 142. The second doped regions 14 on both sides and at the bottom of the first doped region 13 are conducted mutually, so that the electrode electrically connected with the second doped region 14 is only required to be arranged on one side of the ridge portion 11, and is universal to the electrode of the electro-optical modulator designed by a common PN junction, and no extra parasitic capacitance is introduced, so that the modulation bandwidth is prevented from being influenced by the extra capacitance. Although increasing the number of PN junctions affects junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be achieved by designing the appropriate modulation length.
In this embodiment, as in the embodiment, the plurality of vertical doped regions 135 are arranged at equal intervals along the extending direction of the ridge portion 11, and the duty ratio of the vertical doped regions 135 is 20% to 80%. The plate portion 12 between each of the vertical doped regions 135 is an intrinsic region 15, and the width D of the intrinsic region 15 is greater than or equal to 500nm, i.e., the distance D between the first heavily doped region and the second heavily doped region 14 is at least 500nm, so as to minimize optical loss. Of course, in other embodiments, the intrinsic region 15 may be lightly doped, and the first lightly doped region is replaced by a first lightly doped region, and the doping type of the first lightly doped region is the same as that of the first doped region, and the doping concentration of the first lightly doped region is smaller than that of the first doped region.
In this embodiment, the cross section of the middle doped region 134 of the first doped region 13 is rectangular, and in other embodiments, the middle doped region 134 of the first doped region 13 may further include a vertical region and a horizontal region, where the vertical region and the horizontal region are connected to form a cross-shape, a "soil" shape, a "dry" shape, a "king" shape, a "T" shape, an "E" shape, an "L" shape, a "Z" shape, and the like. The horizontal region of the middle doped region is adjacent to the bottom doped region of the second doped region to form a PN junction in the horizontal direction, the vertical region of the middle doped region is adjacent to the two side doped regions of the second doped region to form a PN junction in the vertical direction, and the vertical doped regions are arranged in one side doped region of the second doped region at intervals and are adjacent to the side doped regions to form a plurality of PN junctions in the vertical direction.
Example 6
As shown in fig. 10 and 11, in this embodiment, as in embodiment 5, the first doped region 13 includes a middle doped region 134 (which may include a horizontal region and a vertical region) provided in the ridge portion 11 and extending in the extending direction of the ridge portion 11 (i.e., the illustrated y-axis direction), and a plurality of vertical doped regions 135 (like the vertical regions in the above embodiments) provided at intervals in the extending direction of the ridge portion 11, the vertical doped regions 135 extending into the flat plate portion 12 on one side of the ridge portion 11 in a direction perpendicular to the extending direction of the ridge portion 11 (i.e., the illustrated x-axis direction), the vertical doped regions 135 being connected to the middle doped region 134.
Unlike embodiment 5, in this embodiment, the second doped region 14 includes two side doped regions 141 provided in the ridge portion 11 on both sides of the middle doped region 134 of the first doped region 13, respectively, and a top doped region 143 provided above the first doped region 13, the two side doped regions 141 being connected by the top doped region 143. The second doped region 14 extends into the plate portion 12 on the other side opposite the vertical doped region 135. The two side doped regions 141 of the second doped region 14 are respectively adjacent to the middle doped region 134 and the vertical doped region 135 of the first doped region 13, forming a PN junction including a vertical direction P2 and a vertical direction P3; the top doped region 143 of the second doped region 14 adjoins the middle doped region 134 of the first doped region 13, forming a PN junction in the horizontal direction P1.
In this embodiment, the width d of the side doped 141 region of the second doped region 14 is greater than or equal to 50nm, the thickness h of the top doped region 143 is greater than or equal to 50nm, and the two side doped regions 141 are connected by the top doped region 143. That is, the second doped regions 14 on both sides and on the top of the first doped region 13 are conducted mutually, so that the electrode electrically connected with the second doped region 14 is only required to be arranged on one side of the ridge portion 11, and is universal to the electrode of the electro-optical modulator designed by a common PN junction, and no extra parasitic capacitance is introduced, so that the modulation bandwidth is prevented from being influenced by the extra capacitance. Although increasing the number of PN junctions affects junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be achieved by designing the appropriate modulation length. In this embodiment, the height of the vertical doped region 135 of the first doped region 13 is the same as that of the side doped region 141 of the second doped region 14, and the vertical doped region 135 extends into the top doped region 143 of the second doped region 14 to divide the top doped region 143 of the second doped region 14 into a comb-like structure, and the vertical doped region 135 is also adjacent to the top doped region 143 to form a PN junction in the vertical direction, so that the area of the PN junction in the vertical direction is increased.
Example 7
As shown in fig. 12 and 13, unlike embodiment 6, in this embodiment, the height of the vertical doped region 135 of the first doped region 13 is lower than the height of the side doped region 141 of the second doped region 14, and is equal to the height of the middle doped region 134 of the first doped region 13. The doping structure is relatively simple and the production is convenient.
In embodiments 5-7, the second doped region includes two side doped regions and one top doped region or one bottom doped region, and in other embodiments, the second doped region may also include both the bottom doped region and the top doped region. The bottom doped region and the top doped region may both be connected to both side doped regions at the same time, or one of the top doped region and the bottom doped region may be connected to both side doped regions at the same time, and the other may be connected to at least one of the side doped regions.
Example 8
As shown in fig. 14, unlike embodiment 1, the ridge waveguide of the electro-optic modulator in this embodiment further includes a first intermediate doped region 18 and a second intermediate doped region 19. Wherein the first middle doped region 18 is located between the first doped region 13 and the first heavily doped region 16, and is connected to the end of the vertical region 133. The first middle doped region 18 has the same doping type as the first doped region 13, and has a doping concentration higher than that of the first doped region 13 and lower than that of the first heavily doped region 16. The second middle doped region 19 is located between the second doped region 14 and the second heavily doped region 17, and the doping type of the second middle doped region 19 is the same as that of the second doped region 14, and the doping concentration is higher than that of the second doped region 14 and lower than that of the second heavily doped region 17. Here, the doping concentration of the first doped region 13 and the second doped region 14 is 1×10 17 cm -3 ～9×10 18 cm -3 Within the range, the doping concentration of the first intermediate doped region 18 and the second intermediate doped region 19 is 1×10 18 cm -3 ～9×10 19 cm -3 Within the range, the doping concentration of the first heavily doped region 16 and the second heavily doped region 17 is 5×10 19 cm -3 ～1×10 21 cm -3 Within the range.
In this embodiment, the extension length of the vertical region 133 of the first doped region 13 into the plate portion, i.e., the width D of the intrinsic region 15, is in the range of 0 to 500nm, i.e., the spacing D between the first intermediate doped region 18 and the second doped region 14 is in the range of 0 to 500nm. In other embodiments, the intrinsic region 15 may also be lightly doped, replaced by a first lightly doped region, the first lightly doped regionThe doping type of the impurity region is the same as that of the first doping region, and the doping concentration is 1×10 16 cm -3 ～1×10 17 cm -3 Within the range.
In the above embodiments, the ridge portion width of the ridge waveguide is preferably in the range of 300 to 600nm, the P-type doping is preferably boron as the doping impurity, and the N-type doping is preferably phosphorus as the doping impurity.
The above list of detailed descriptions is only specific to practical embodiments of the present application, and they are not intended to limit the scope of the present application, and all equivalent embodiments or modifications that do not depart from the spirit of the technical spirit of the present application are included in the scope of the present application.
Claims (17)
1. An electro-optic modulator, characterized by: the ridge waveguide comprises a ridge part and flat plate parts positioned at two sides of the ridge part;
a first doping region and a second doping region are arranged in the ridge waveguide, and the doping types of the first doping region and the second doping region are opposite;
the first doping region comprises a vertical region and a horizontal region which are arranged in the ridge part and extend along the extending direction of the ridge part, and a plurality of vertical regions which are arranged at intervals along the extending direction of the ridge part, wherein the vertical regions extend into a flat plate part on one side of the ridge part along the direction perpendicular to the extending direction of the ridge part;
the horizontal region, the vertical region and the vertical region are mutually connected together, the bottoms of the horizontal region and the vertical region are higher than the bottom of the ridge waveguide, and the width of the horizontal region is smaller than the width of the ridge part;
the second doped region includes a portion of the ridge portion other than the first doped region, the second doped region extending into the flat plate portion on the other side opposite the vertical region;
the second doped region is adjacent to the horizontal region, the vertical region and the vertical region of the first doped region to form PN junctions respectively comprising a horizontal direction, a vertical direction and a vertical direction.
2. An electro-optic modulator as claimed in claim 1, wherein: the horizontal region of the first doped region is located at the bottom, middle or top of the vertical region.
3. An electro-optic modulator as claimed in claim 2, wherein: the horizontal region of the first doped region is located at one side or two sides of the vertical region.
4. An electro-optic modulator as claimed in claim 1, wherein: the bottoms of the horizontal and vertical regions of the first doped region are at least 50nm higher than the bottom of the ridge waveguide.
5. An electro-optic modulator as claimed in claim 1, wherein: the thickness of the horizontal region of the first doped region is greater than or equal to 30nm.
6. An electro-optic modulator as claimed in claim 1, wherein: the plurality of vertical regions are disposed at equal intervals along an extending direction of the ridge portion.
7. An electro-optic modulator as claimed in claim 6, wherein: the duty cycle of the vertical region is 20% -80%.
8. An electro-optic modulator as claimed in claim 1, wherein: the flat plate part where the vertical region is located is an intrinsic region or a first lightly doped region; the first lightly doped region is the same as the first doped region in doping type.
9. An electro-optic modulator as claimed in claim 1, wherein: the width of the horizontal region is greater than or equal to the width of the vertical region.
10. An electro-optic modulator as claimed in any one of claims 1 to 9 wherein:
the ridge waveguide further includes a first heavily doped region and a second heavily doped region:
the first heavily doped region is positioned outside the vertical region of the first doped region and connected with the tail end of the vertical region, the doping type of the first heavily doped region is the same as that of the first doped region, and the doping concentration of the first heavily doped region is higher than that of the first doped region;
the second heavily doped region is positioned outside the second doped region and connected with the second doped region, the doping types of the second heavily doped region and the second doped region are the same, and the doping concentration of the second heavily doped region is higher than that of the second doped region;
the electro-optic modulator further includes at least two electrodes, the first heavily doped region and the second heavily doped region being electrically connected to the two electrodes, respectively.
11. An electro-optic modulator as claimed in claim 10, wherein: the extension length of the vertical region extending into the flat plate portion is greater than or equal to 500nm.
12. An electro-optic modulator as claimed in claim 10, wherein:
the ridge waveguide further includes a first intermediate doped region and a second intermediate doped region:
the first middle doping region is positioned between the first doping region and the first heavy doping region and connected with the tail end of the vertical region, the doping types of the first middle doping region and the first doping region are the same, and the doping concentration of the first middle doping region is higher than that of the first doping region and lower than that of the first heavy doping region;
the second middle doping region is positioned between the second doping region and the second heavily doping region, the doping types of the second middle doping region and the second doping region are the same, and the doping concentration of the second middle doping region is higher than that of the second doping region and lower than that of the second heavily doping region.
13. An electro-optic modulator as claimed in claim 12, wherein: the extension length of the vertical region extending into the flat plate portion is between 0 and 500nm.
14. An electro-optic modulator, characterized by: the ridge waveguide comprises a ridge part and flat plate parts positioned at two sides of the ridge part;
a first doping region and a second doping region are arranged in the ridge waveguide, and the doping types of the first doping region and the second doping region are opposite;
the first doped region comprises a middle doped region which is arranged in the ridge part and extends along the extending direction of the ridge part, and a plurality of vertical doped regions which are arranged at intervals along the extending direction of the ridge part, wherein the vertical doped regions extend into a flat plate part on one side of the ridge part along the direction perpendicular to the extending direction of the ridge part; the vertical doped region is connected with the middle doped region;
the second doped region comprises two side doped regions which are arranged in the ridge part and are respectively positioned at two sides of the middle doped region of the first doped region, and a top doped region positioned above the first doped region and/or a bottom doped region positioned below the first doped region; the two side doped regions are connected through the top doped region and/or the bottom doped region; the second doped region extends into the flat plate part at the other side opposite to the vertical doped region; the second doped region adjoins the first doped region to form a PN junction including a horizontal direction, a vertical direction and a vertical direction.
15. An electro-optic modulator as claimed in claim 14, wherein: the cross section of the middle doped region of the first doped region is rectangular; or the middle doped region of the first doped region comprises a vertical region and a horizontal region, and the vertical region and the horizontal region are connected.
16. An electro-optic modulator as claimed in claim 14, wherein: the flat plate part where the vertical doping region is located is an intrinsic region or a first lightly doped region; the first lightly doped region is the same as the first doped region in doping type.
17. An electro-optic modulator as claimed in claim 14, wherein: the second doped region has a width of the side doped region greater than or equal to 50nm and at least one of the top doped region and the bottom doped region has a thickness greater than or equal to 50nm.
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| GB9515147D0 (en) * | 1994-07-25 | 1995-09-20 | Hyundai Electronics Ind | Semiconductor device and method of manufacturing the same |
| CN1941438A (en) * | 2005-09-29 | 2007-04-04 | 株式会社东芝 | Semiconductor light-emitting device and producing method for the same |
| CN101006382A (en) * | 2004-08-16 | 2007-07-25 | 卢森特技术有限公司 | High-speed semiconductor waveguide phase-shifter |
| CN103226252A (en) * | 2013-05-06 | 2013-07-31 | 中国科学院半导体研究所 | Doping structure capable of improving modulation efficiency of depletion silicon-based electrooptical modulator |
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| SG2013082102A (en) * | 2012-11-05 | 2014-06-27 | Agency Science Tech & Res | Method for forming an optical modulator |
| US10027420B2 (en) * | 2014-06-26 | 2018-07-17 | Luxtera, Inc. | Method and system for a silicon-based optical phase modulator with high modal overlap |
| FR3078437B1 (en) * | 2018-02-23 | 2022-02-04 | St Microelectronics Crolles 2 Sas | PN JUNCTION |
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|---|---|---|---|---|
| GB9515147D0 (en) * | 1994-07-25 | 1995-09-20 | Hyundai Electronics Ind | Semiconductor device and method of manufacturing the same |
| CN101006382A (en) * | 2004-08-16 | 2007-07-25 | 卢森特技术有限公司 | High-speed semiconductor waveguide phase-shifter |
| CN1941438A (en) * | 2005-09-29 | 2007-04-04 | 株式会社东芝 | Semiconductor light-emitting device and producing method for the same |
| CN103226252A (en) * | 2013-05-06 | 2013-07-31 | 中国科学院半导体研究所 | Doping structure capable of improving modulation efficiency of depletion silicon-based electrooptical modulator |
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