TW202316760A - Ridge/buried hybrid DFB semiconductor laser epitaxy manufacturing method and DFB semiconductor laser structure made by the same capable of improving the process yield and reliability - Google Patents

Abstract

The present invention provides a ridge/buried hybrid DFB semiconductor laser epitaxy manufacturing method, which is to sequentially form an N-type material region, an active region and a P-type material region on a substrate by epitaxial growth in order to form a double heterojunction structure, and the P-type material region has an etching stop layer and a P-type upper isolation layer in sequence from bottom to top. A (grating) tunnel junction (TJ) layer is adjacently arranged on the P-type upper isolation layer, and the TJ layer and the P-type upper isolation layer are etched to be stopped at the etch stop layer to form a ridge, so that the active region is not etched and a light-emitting range is not narrowed. An N-type cladding layer and an N-type contact layer are sequentially grown at one time, and the N-type cladding layer buries and covers the ridge, thereby forming a DFB semiconductor laser structure with ridge/buried process characteristics in order to improve the process yield and reliability.

Description

Ridge/Buried Hybrid DFB Semiconductor Laser Epitaxial Manufacturing Method and DFB Semiconductor Laser Structure Made Using It

The present invention is related to DFB (Distributed Feedback Laser Diode, distributed feedback) semiconductor laser, especially a ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method and the DFB semiconductor laser structure made by it .

Optical communication is an electronic communication technology that uses a light source, such as Light Emitting Diode (LED) or semiconductor laser (Laser Diode, LD) as a signal medium, and the commonly used LD is FP (Fabry Perot), There are three types of DFB and vertical cavity surface emission (VCSEL). However, the FP LD and DFB LD of the edge-emitting laser mostly adopt RWG (Ridge Waveguide, ridge waveguide) and BH (Buried Heterojunction, buried heterogeneous) two process methods and respectively correspond to the production structure. Take FP LD as an example , the epitaxial structure roughly includes from bottom to top: a substrate (Substrate), an N-type cladding layer (n-Cladding), an active layer (Active), a P-type cladding layer (p-Cladding) and a P Type contact layer (Contact), and the structural difference between DFB LD and FP LD is mainly: DFB LD is based on FP LD with a Bragg Grating (Bragg Grating) for filtering light to form a single longitudinal mode light output, Therefore, in response to different requirements for optical frequency or optical mode in various optical fiber communications, the Bragg grating is selected to be disposed within the range of the N-type cladding layer or the P-type cladding layer according to the requirements.

Among them, in the RWG structure, an etching stop layer (Etching Stop) is buried in the P-type draping layer and divided into upper and lower parts, and a part of the P-type contact layer and the upper part are separated by etching. The P-type cladding layer is removed and stopped at the etch stop layer to form a Ridge structure; in the BH structure, after a part of the P-type cladding layer and the active layer are removed, one regrowth p/n InP and secondary regrowth of p InP to complete the P-type cladding layer and form the P-type contact layer. It can be seen that the obvious characteristics of the RWG LD structure are to maintain the integrity of the active layer, and it has the advantages of relatively simple epitaxy process and good stability in the early stage. In the BH LD structure, the active layer is partially etched and removed, and the P-type cladding layer is stacked to cover the active layer to limit the light-emitting area, so as to achieve lower critical current (I _th ) and lower series resistance , higher luminous efficiency and near-circular light spots, etc., but because the P-type cladding layer and the active layer are removed except for the spine part, it involves the need for selective regional epitaxy growth, resulting in complex manufacturing processes. Moreover, it has problems such as poor stability due to the influence of the pnpn type current limiting effect.

In view of this, the inventor of this case considered how to use the above two structures based on factors such as the range of the active layer affecting the quantum efficiency and modulation speed performance, and the fact that the P-type cladding layer has a higher resistance than the N-type cladding layer. The characteristics of DFB are truncated to provide a hybrid structure that combines the advantages of the two structures, so as to improve the traditional DFB structure, improve the process yield and reduce the process cost, which is the subject of the present invention.

In view of the above problems, the purpose of the present invention is to provide a method for epitaxial manufacturing of a ridge/buried hybrid DFB semiconductor laser and the DFB semiconductor laser structure made by it, so as to utilize the tunneling with n-p junction The junction (Tunnel Junction, TJ) structure forms the spine of the RWG structure without etching the active area, so as to optimize the traditional RWG structure and form a BH structure, so that it has both RWG and BH structure characteristics and effectively improves semiconductor heat dissipation efficiency and uniform active area utilization. benefits.

In order to achieve the above purpose, the present invention discloses a ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method, which is to sequentially generate an N-type material region, an active region and a P-type material on a substrate region to form a double heterostructure, which is characterized in that: when epitaxy generates the double heterostructure, a grating layer is arranged in the N-type material region so that the grating layer and the active region form an N-type isolation layer, and An etching stop layer is set in the P-type material region so that a P-type lower isolation layer and a P-type upper isolation layer are respectively formed under and above the etching stop layer; a tunnel junction layer is formed adjacent to the After the P-type upper isolation layer, coat a strip of photoresist on the tunnel junction layer; wherein the tunnel junction layer includes a heavily doped P-type layer and a heavily doped N-type layer, and the heavily doped The impurity P-type layer is adjacent to the P-type upper isolation layer, the heavily doped N-type layer is adjacent to the heavily doped P-type layer; the tunnel junction layer and the After the P-type upper isolation layer is terminated at the etching stop layer to form a spine, the strip photoresist is removed; the active region is not etched and the light-emitting range is not narrowed; After the covering layer and an N-type contact layer, an N-type metal electrode layer is arranged on the N-type contact layer; wherein the N-type cladding layer buries and covers the spine, and the N-type contact layer is arranged on the N-type cladding layer. layer.

Moreover, the etching is anisotropic etching so that the range of the tunnel junction layer of the spine is consistent with the range of the P-type upper isolation layer. In this way, the DFB semiconductor laser structure manufactured by the above-mentioned epitaxial manufacturing method is a semiconductor structure in which the grating is arranged in the N-type material region, and it is characterized in that: in the DFB semiconductor laser structure, the substrate The active region formed by upward epitaxy is not etched to narrow the light-emitting range, so that the active region is larger than the spine, and the spine is the P-type upper isolation layer, the heavily doped P-type layer and the heavily doped N-type layer.

Wherein, the N-type material region sequentially includes a buffer layer, the grating layer, the N-type isolation layer, a first carrier gradient transition layer and a lower confinement layer from bottom to top, and the buffer layer is adjacent to the substrate, the The lower confinement layer is adjacent to the active area; the active area includes a lower gradient layer, a lower energy barrier layer, an active layer, an upper energy barrier layer and an upper gradient layer from bottom to top, and the lower gradient layer is adjacent to the lower Confinement layer, the upper graded layer is adjacent to the P-type material region; the P-type material region sequentially includes an upper confinement layer, the P-type lower isolation layer, the etching stop layer and the P-type upper isolation layer from bottom to top, And the upper confinement layer is adjacent to the upper graded layer; and a second carrier graded transition layer and a third carrier graded transition layer are arranged between the N-type cladding layer and the N-type contact layer from bottom to top. The substrate is made of InP material; the buffer layer and the N-type isolation layer are made of n-InP material, the grating layer is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material, and the first carrier gradient transition layer is made of n- (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material and the lower confinement layer adopt n-In _0.53 Al _0.47 As material; the lower graded layer and the upper graded layer system adopt (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As<-> (Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer and the upper energy barrier layer adopt (Al _0.23 Ga _0.77 ) _0.52 In _0.48 As material and the active layer adopts (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material; the upper confinement layer is made of p-In _0.53 Al _0.47 As material, the P-type lower isolation layer and the P-type upper isolation layer are made of p-InP material, and the etching stop layer is made of p-In _0.84 Ga _0.16 As _0.34 P _0.66 material; the tunnel junction layer is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP; the N-type cladding layer is made of InP material; the second carrier gradient transition layer is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material; the third carrier gradient transition layer is made of n-In _0.61 Ga _0.39 As _0.84 P _0.16 material; and the n-type contact layer is made of n-In _0.53 Ga _0.47 As material.

In addition, the second purpose of the present invention is to disclose a ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method, which is to sequentially generate an N-type material region, an active region and a P-type material region on a substrate. material region to form a double heterostructure, which is characterized in that: when the double heterostructure is formed by epitaxy, an etching stop layer is set in the P-type material region so that an adjacent P layer is formed under and above the etching stop layer. Type lower isolation layer and a P-type upper isolation layer; after forming a grating tunnel junction layer with a grating structure adjacent to the P-type upper isolation layer, coating a strip of photoresist on the grating tunnel junction layer above; wherein the grating tunnel junction layer includes a heavily doped grating P-type layer and a heavily doped grating N-type layer, and the heavily doped grating P-type layer is adjacent to the P-type upper isolation layer, and the heavily doped grating The N-type layer is adjacent to the P-type layer of the heavily doped grating; the grating tunnel junction layer and the P-type upper isolation layer that are not covered by the strip photoresist are etched downward and stop at the etching stop layer to form After a spine, the strip photoresist is removed; the active area is not etched and the light emitting range is not reduced; and after one-time regrowth and an N-type cladding layer and an N-type contact layer are sequentially formed, an N-type The metal electrode layer is on the N-type contact layer; wherein the N-type cladding layer buries and covers the spine, and the N-type contact layer is arranged on the N-type cladding layer.

Moreover, the etching is anisotropic etching so that the range of the grating tunnel junction layer of the spine is consistent with the range of the P-type upper isolation layer. In this way, the DFB semiconductor laser structure made by the above-mentioned epitaxial manufacturing method is a semiconductor structure in which the grating is arranged on the P-type material region, and it is characterized in that: in the DFB semiconductor laser structure, the substrate The active region formed by upward epitaxy is not etched to narrow the light-emitting range, so that the active region is larger than the spine, and the spine is the P-type upper isolation layer, the heavily doped grating P type layer and the N-type layer of the heavily doped grating.

Wherein, the N-type material region includes a buffer layer, a first carrier gradient transition layer and a lower confinement layer in sequence from bottom to top, and the buffer layer is adjacent to the substrate, and the lower confinement layer is adjacent to the active region; the active The region includes a lower gradient layer, a lower energy barrier layer, an active layer, an upper energy barrier layer, and an upper gradient layer from bottom to top, and the lower gradient layer is adjacent to the lower confinement layer, and the upper gradient layer is adjacent to the P The P-type material region; the P-type material region sequentially includes an upper confinement layer, the P-type lower isolation layer, the etch stop layer, and the P-type upper isolation layer from bottom to top, and the upper confinement layer is adjacent to the upper graded layer ; and between the N-type cladding layer and the N-type contact layer, a second carrier gradient transition layer and a third carrier gradient transition layer are arranged from bottom to top. The substrate is made of InP material; the buffer layer is made of n-InP material, the first carrier gradient transition layer is made of n-(Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material and the lower confinement layer is made of n-In _0.53 Al _0.47 As material; the lower graded layer and the upper graded layer are made of (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As <-> (Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer and the upper energy barrier layer is made of (Al _0.23 Ga _0.77 ) _0.52 In _0.48 As material and the active layer is made of (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material; the upper confinement layer is made of p-In _0.53 Al _0.47 As material, the P-type lower isolation Layer and the P-type upper isolation layer are made of p-InP material, the etching stop layer is made of p-In _0.84 Ga _0.16 As _0.34 P _0.66 material; the grating tunnel junction layer is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP material; the N-type cladding layer is made of InP material; the second carrier gradient transition layer system is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material; the third carrier gradient transition layer system is made of n-In _0.61 Ga _0.39 As _0.84 P _0.16 material; and the n-type contact layer adopts n-In _0.53 Ga _0.47 As material. The P-type layer of the heavily doped grating adopts p-In _0.71 Ga _0.29 As _0.62 P _0.38 material, and the N-type layer of the heavily doped grating adopts n-In _0.71 Ga _0.29 As _0.62 P _0.38 material.

To sum up, the present invention provides two different grating forming processes in response to different light type requirements, allowing components to choose to set the grating in the range of P-type or N-type semiconductor materials due to different requirements. When the second-class epitaxial manufacturing method etches the (grating) tunnel junction layer with np junction and the p-type upper isolation layer to form the spine, it does not reduce the range of the active region and greatly reduces the area of the p-type material region The scope is reduced, so as to improve the internal quantum efficiency of the active layer and achieve the purpose of improving the overall yield and reliability. Moreover, through the setting of the heavily doped (grating) NP-type layer of the (grating) tunnel junction layer, the secondary regrowth process of the traditional BH structure is simplified and only one regrowth is required, which effectively simplifies the epitaxy The complexity of the crystal process improves the overall process performance. When growing again, replace the p InP/InGaAs used in the traditional BH structure with n InP/InGaAs, which is to convert the P-type cladding layer and P-type contact layer in the traditional BH structure into N-type cladding layer and N-type contact layer. Layer, through the characteristics of low resistance and high heat dissipation efficiency of N-type materials, DFB LD can achieve high carrier transmission efficiency, low I _th , low series resistance, high luminous efficiency, approximately circular light spot and high heat dissipation efficiency. And further realize the effect of improving the process yield and reliability of DFB semiconductor laser.

In order to enable those skilled in the art to clearly understand the content of the present invention, the following descriptions are provided together with the drawings for your reference.

Please refer to Figures 1 to 3, which are respectively a flowchart of a preferred embodiment of the present invention and a schematic diagram of the epitaxy state process and a schematic structural diagram of a second preferred embodiment. As shown in the figure, the epitaxial manufacturing method of the ridge/buried hybrid DFB semiconductor laser includes the following steps: step S10, sequentially epitaxially generating an N-type material region 11 and an active region 12 on a substrate 10 and a P-type material region 13 to form a double heterostructure, and step S11, when epitaxially generating the double heterostructure, is to set a grating layer 111 in the N-type material region 11 so that the grating layer 111 and the active An N-type isolation layer 112 is formed between the regions 12 . Step S12 , disposing an etch stop layer 132 in the P-type material region 13 so that a P-type lower isolation layer 131 and a P-type upper isolation layer 133 are respectively formed under and above the etch stop layer 132 . Step S13, after forming a tunnel junction layer 140 adjacent to the P-type upper isolation layer 133, coating a strip of photoresist 2 on the tunnel junction layer 140; wherein the tunnel junction layer 140 includes A heavily doped P-type layer 1400 and a heavily doped N-type layer 1401, and the heavily doped P-type layer 1400 is adjacent to the P-type upper isolation layer 133, and the heavily doped N-type layer 1401 is adjacent to the heavily doped P-type Layer 1400 on. Step S14, etching down the tunnel junction layer 140 and the P-type upper isolation layer 133 not covering the strip photoresist 2 and stopping at the etching stop layer 132 to form a spine, and removing the strip photoresist Resistance 2; wherein the active region 12 has not been etched and has not narrowed the range of light emission. Step S15, after forming an N-type cladding layer 15 and an N-type contact layer 18 sequentially in one-time regrowth, an N-type metal electrode layer 19 is arranged on the N-type contact layer 18; wherein the N-type cladding layer 15 bury and cover the spine, and the N-type contact layer 18 is disposed on the N-type cladding layer 15 .

Thus, the DFB semiconductor laser structure 1 manufactured by the above-mentioned epitaxial manufacturing method is a semiconductor structure in which the grating is disposed in the N-type material region 11, and the active region 12 is epitaxially formed upward from the substrate 10. The light-emitting range is narrowed without being etched, so that the range of the active region 12 is larger than the range of the spine, which can effectively increase the carrier transmission efficiency and improve the heat dissipation effect. In other words, since the process does not etch to the range of the active region 12, logically the overall process yield and reliability can be improved. And, the spine is the P-type upper isolation layer 133, the heavily doped P-type layer 1400 and the heavily doped N-type layer 1401 in sequence from bottom to top, and the etching is anisotropic etching so that the spine The tunnel junction layer 140 is in the same range as the P-type upper isolation layer 133 . Here, according to the characteristics that the heavily doped P-type layer 1400 is adjacent to the P-type upper isolation layer 133, and the heavily doped N-type layer 1401 is adjacent to the heavily doped P-type layer 1400, the cladding can be further transposed. The N-type cladding layer 15 and the N-type contact layer 18 are used to simplify the secondary regrowth process of the conventional BH structure into one-time growth.

Furthermore, based on the above-mentioned process means, various functional layers can be expanded in this semiconductor structure, and then a DFB LD element with better overall efficiency can be realized in detail. In this embodiment, in order to reduce the adverse effect caused by the difference in lattice constant and thermal expansion coefficient between the substrate 10 and the semiconductor material, and to effectively improve the carrier transmission efficiency, a buffer layer (Buffer) and Carrier graded transition layer, etc., thereby improving its epitaxial electrical and optical properties. Therefore, the N-type material region 11 may include a buffer layer 110, the grating layer 111, the N-type isolation layer 112, a first carrier gradient transition layer 113 and a lower confinement layer 114 in sequence from bottom to top, and The buffer layer 110 is adjacent to the substrate 10 , and the lower confinement layer 114 is adjacent to the active region 12 . In addition, in order to improve the light confinement effect after the active region 12 emits light, this specific structure adds a barrier layer (Barrier) and the gradient layer (GRIN). Therefore, the active region 12 sequentially includes the following gradient layers 120 from bottom to top , a lower energy barrier layer 121, an active layer 122, an upper energy barrier layer 123, and an upper graded layer 124, and the lower graded layer 120 is adjacent to the lower confinement layer 114, and the upper graded layer 124 is adjacent to the P-type material region 13 . The P-type material region 13 includes an upper confinement layer 130, the P-type lower isolation layer 131, the etch stop layer 132, and the P-type upper isolation layer 133 from bottom to top, and the upper confinement layer 130 is adjacent to the upper Gradient layer 124. Moreover, a second carrier gradient transition layer 16 and a third carrier gradient transition layer 17 are further disposed between the N-type cladding layer 15 and the N-type contact layer 18 from bottom to top.

Wherein, the substrate 10 can be made of InP material; the buffer layer 110 and the N-type isolation layer 112 can be made of n-InP material; the grating 111 layer can be made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material; The transition layer 113 is made of n-(Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material and the lower confinement layer 114 is made of n-In _0.53 Al _0.47 As material. The lower graded layer 120 and the upper graded layer 124 are made of (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As <-> (Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer 121 and the upper energy barrier layer 123 is made of (Al _0.23 Ga _0.77 ) _0.52 In _0.48 As material and the active layer 122 is made of (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material. The upper confinement layer 130 is made of p-In _0.53 Al _0.47 As material, the P-type lower isolation layer 131 and the P-type upper isolation layer 133 are made of p-InP material, and the etching stop layer 132 is made of p-In _0.84 Ga _0.16 As _0.34 P _0.66 material. The tunnel junction layer 140 is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP material, the N-type cladding layer 15 is made of InP material, and the second carrier gradient transition layer 16 is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material, the third carrier gradient transition layer 17 is made of n-In _0.61 Ga _0.39 As _0.84 P _0.16 material, and the N-type contact layer 18 is made of n-In _0.53 Ga _0.47 As material.

Please refer to Figures 4-6, which are respectively the flow charts of the three preferred embodiments of the present invention and the schematic diagrams of the epitaxial state process and the structure of the four preferred embodiments. As shown in the figure, the DFB semiconductor laser structure 1 made by the ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method is a structure in which the grating is arranged on the P-type semiconductor material, which is from bottom to bottom It includes a substrate 10, an N-type material region 11, an active region 12, a P-type material region 13, a grating tunnel junction layer 141, an N-type cladding layer 15, and an N-type contact layer 18 in sequence. And an N-type metal electrode layer 19, to simplify the secondary regrowth process of the traditional BH structure by using the grating TJ structure with n-p junction, and transpose the P-type cladding layer and P-type contact layer to N-type, so that the To optimize the manufacturing process and improve the efficiency of carrier transport and heat dissipation, the epitaxial manufacturing method of the ridge/buried hybrid DFB semiconductor laser may include the following steps.

In step S20, an N-type material region 11, an active region 12, and a P-type material region 13 are sequentially epitaxially formed on the substrate 10 to form a double heterostructure, and when the double heterostructure is formed by epitaxy, step S21 An etching stop layer 132 is disposed in the P-type material region 13 so that a P-type lower isolation layer 131 and a P-type upper isolation layer 133 are respectively formed under and above the etching stop layer 132 . Step S22, after forming a grating tunnel junction layer 141 with a grating structure adjacent to the P-type upper isolation layer 133, coating a strip of photoresist 2 on the grating tunnel junction layer 141, and the grating The tunnel junction layer 141 includes a heavily doped grating P-type layer 1410 and a heavily doped grating N-type layer 1411, and the heavily doped grating P-type layer 1410 is adjacent to the P-type upper isolation layer 133, and the heavily doped grating The N-type layer 1411 is adjacent to the P-type layer 1410 of the heavily doped grating.

Step S23, etching down the grating tunnel junction layer 141 and the P-type upper isolation layer 133 not covering the strip photoresist 2 and stopping at the etching stop layer 132 to form a spine, and removing the strip The photoresist 2, wherein the active region 12 is not etched and the light emitting range is not narrowed. Step S24, one-time regrowth to form an N-type cladding layer 15 and an N-type contact layer 18 in sequence, so that the N-type cladding layer 15 buries and covers the spine, and the N-type contact layer 18 is arranged on the N-type. After the N-type cladding layer 15 is formed, step S25 is to arrange an N-type metal electrode layer 19 on the N-type contact layer 18 . Since the etching is anisotropic etching in the manufacturing process so that the range of the grating tunnel junction layer 141 of the spine is consistent with that of the P-type upper isolation layer 133, it can be seen that in the DFB semiconductor laser structure 1, the substrate 10 The active region 12 formed by upward epitaxy is not etched to narrow the light-emitting range, so that the active region 12 is larger than the spine, and the spine is the P-type upper isolation layer 133, the heavy Doping the P-type layer 1410 of the grating and the N-type layer 1411 of the heavily doped grating is used to gradually and successfully transpose the P-type cladding layer in the conventional BH structure to the N-type one.

In this embodiment, the above-mentioned process means can be used as the basis, and then various functional layers can be expanded in this semiconductor structure. For example, the substrate 10 can be made of InP material, and in order to reduce the distance between the substrate 10 and the semiconductor material. In consideration of the adverse effects caused by the difference in lattice constant and thermal expansion coefficient and effectively improving the carrier transport efficiency, a buffer layer (Buffer) and a gradual carrier transition layer can be set between the structure of the substrate 10 and the N-type material region 11, etc., To improve its epitaxial electrical and optical properties. Therefore, the N-type material region 11 includes, from bottom to top, a buffer layer 110 made of n-InP material, a first carrier graded transition layer made of n-(Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material 113 and a lower confinement layer 114 made of n-In _0.53 Al _0.47 As material, and the buffer layer 110 is adjacent to the substrate 10 , and the lower confinement layer 114 is adjacent to the active region 12 . In order to improve the light confinement effect after the active region 12 emits light, an energy barrier layer and a gradient layer are added in this specific structure, so that the active region 12 can include a lower gradient layer 120, a lower energy barrier layer 121, a lower gradient layer in sequence from bottom to top. Active layer 122, an upper barrier layer 123 and an upper graded layer 124, the lower graded layer 120 is adjacent to the lower confinement layer 114, the upper graded layer 124 is adjacent to the P-type material region 13, and the lower graded layer 120 and the The upper graded layer 124 is made of (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As <-> (Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer 121 and the upper energy barrier layer 123 are made of (Al _0.23 Ga _0.77 ) _{The 0.52} In _0.48 As material and the active layer 122 are made of (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material. The P-type material region 13 includes, from bottom to top, an upper confinement layer 130 made of p-In _0.53 Al _0.47 As material, the P-type lower isolation layer 131, and a p-In _0.84 Ga _0.16 As _0.34 P _0.66 material. The etch stop layer 132 and the P-type upper isolation layer 133 , and the P-type lower isolation layer 131 and the P-type upper isolation layer 133 are made of p-InP material, and the upper confinement layer 130 is adjacent to the upper graded layer 124 . The grating tunnel junction layer 141 is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP material, and the heavily doped grating P-type layer 1410 is made of p-In _0.71 Ga _0.29 As _0.62 P _0.38 material, and the heavily doped grating N Type 1411 layer adopts n-In _0.71 Ga _0.29 As _0.62 P _0.38 material. Furthermore, a second carrier gradient transition layer 16 and a first carrier transition layer 16 are arranged from bottom to top between the N-type cladding layer 15 made of InP material and the N-type contact layer 18 made of n-In _0.53 Ga _0.47 As material. Three carrier graded transition layers 17, and the second carrier graded transition layer 16 is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material, and the third carrier graded transition layer 17 is made of n-In _0.61 Ga _0.39 As _0.84 P _0.16 material, the epitaxial quality is guaranteed by gradually changing the energy level, and then the DFB LD device with better overall efficiency can be realized in detail.

To sum up, the process of the present invention does not etch the active region 12 and does not narrow the light-emitting range of the active layer 122, so that the overall process yield and reliability can be improved. Moreover, the N-type cladding layer 15 completely buries and covers the spine, and the N-type contact layer 18 is disposed on the N-type cladding layer 15. In this way, the coupling between the optical field and the quantum well of the active layer 122 can be improved. It tends to the middle position of the active layer 122, so that the lower half of the active layer 122 can be effectively used to compensate the optical field offset in the vertical direction, so as to increase the modal gain and reduce I _th .

The above is only a description of the preferred embodiment in the patent scope of the present invention, but not to limit the scope of rights of the present invention based on the content of this embodiment; therefore, the textual changes made without departing from the equivalent scope of the present invention or modifications, should still be covered within the scope of the patent application of the present invention.

1: DFB semiconductor laser structure 10: Substrate 11: N-type material area 110: buffer layer 111: Grating layer 112: N-type isolation layer 113: The first carrier gradient transition layer 114: lower limited layer 12: Active area 120: lower gradient layer 121: Lower barrier layer 122: active layer 123: Upper barrier layer 124: upper gradient layer 13: P-type material area 130: upper limited layer 131: P-type lower isolation layer 132: etch stop layer 133: P-type upper isolation layer 140: Tunnel junction layer 1400: heavily doped P-type layer 1401: heavily doped N-type layer 141: Grating Tunneling Junction Layer 1410: heavily doped grating P-type layer 1411: heavily doped grating n-type layer 15: N-type cladding layer 16: The second carrier gradient transition layer 17: The third carrier gradient transition layer 18: N-type contact layer 19: N-type metal electrode layer 2: Strip photoresist S10～S15, S20～S25: steps

Fig. 1 is a flowchart of a preferred embodiment of the present invention. Figures 2A, 2B, and 2C are schematic diagrams of the epitaxy state flow chart of the second preferred embodiment of the present invention. Fig. 3 is a structural schematic diagram of a second preferred embodiment of the present invention. Fig. 4 is a flowchart of three preferred embodiments of the present invention. Figures 5A and 5B are schematic diagrams of epitaxy state flow charts in four preferred embodiments of the present invention. Fig. 6 is a structural schematic view of four preferred embodiments of the present invention.

S10~S15: Steps

Claims (11)

A ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method is to sequentially epitaxially generate an N-type material region, an active region, and a P-type material region on a substrate to form a double heterostructure. Features: When forming the double heterostructure by epitaxy, a grating layer is set in the N-type material region so that the grating layer and the active region form an N-type isolation layer, and an etching stop layer is set in the P-type material region A P-type lower isolation layer and a P-type upper isolation layer are respectively formed under and above the etching stop layer; After forming a tunnel junction layer adjacent to the P-type upper isolation layer, a strip of photoresist is coated on the tunnel junction layer; wherein the tunnel junction layer includes a heavily doped P-type layer and a heavily doped A doped N-type layer, and the heavily doped P-type layer is adjacent to the P-type upper isolation layer, and the heavily doped N-type layer is adjacent to the heavily doped P-type layer; After etching down the tunnel junction layer and the P-type upper isolation layer not covering the strip-shaped photoresist and stopping at the etching stop layer to form a spine, remove the strip-shaped photoresist; wherein the active region is not etched without reducing the area of light emission; and After forming an N-type cladding layer and an N-type contact layer in sequence by one-time regrowth, an N-type metal electrode layer is arranged on the N-type contact layer; wherein the N-type cladding layer buries and covers the spine, the The N-type contact layer is disposed on the N-type cladding layer. The epitaxial manufacturing method according to claim 1, wherein the etching is anisotropic etching so that the tunnel junction layer of the spine is in the same range as the P-type upper isolation layer. A DFB semiconductor laser structure made by using the epitaxial manufacturing method described in any one of claims 1 and 2, characterized in that: in the DFB semiconductor laser structure, the substrate is epitaxially formed The active region is not etched to narrow the light-emitting range, so that the active region is larger than the spine, and the spine is the P-type upper isolation layer, the heavily doped P-type layer, and the heavily doped heterogeneous N-type layer. The DFB semiconductor laser structure according to claim 3, wherein the N-type material region sequentially includes a buffer layer, the grating layer, the N-type isolation layer, a first carrier gradient transition layer and A lower confinement layer, and the buffer layer is adjacent to the substrate, and the lower confinement layer is adjacent to the active region; the active region includes a lower gradient layer, a lower energy barrier layer, an active layer, an upper energy barrier layer and An upper graded layer, and the lower graded layer is adjacent to the lower confinement layer, and the upper graded layer is adjacent to the P-type material region; the P-type material region sequentially includes an upper confinement layer, the P-type lower isolation layer , the etch stop layer and the P-type upper isolation layer, and the upper confinement layer is adjacent to the upper graded layer; and a second carrier is further provided between the N-type cladding layer and the N-type contact layer from bottom to top a graded transition layer and a third carrier graded transition layer. The DFB semiconductor laser structure as described in Claim 4, wherein the substrate is made of InP material; the buffer layer and the N-type isolation layer are made of n-InP material, and the grating layer is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material, the first carrier graded transition layer is made of n-(Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material and the lower confinement layer is made of n-In _0.53 Al _0.47 As material; the lower graded layer and the upper graded layer (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As <-> (Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer and the upper energy barrier layer are (Al _0.23 Ga _0.77 ) _0.52 In _0.48 As material And the active layer is made of (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material; the upper confinement layer is made of p-In _0.53 Al _0.47 As material, the P-type lower isolation layer and the P-type upper isolation layer are made of p-InP material , The etching stop layer is made of p-In _0.84 Ga _0.16 As _0.34 P _0.66 material; the tunnel junction layer is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP material; the N-type cladding layer is made of InP material; The second carrier gradient transition layer system uses n-In _0.71 Ga _0.29 As _0.62 P _0.38 material; the third carrier gradient transition layer system uses n-In _0.61 Ga _0.39 As _0.84 P _0.16 material; and the N-type contact layer system uses n-In _0.53 Ga _0.47 As material. A ridge/buried hybrid DFB semiconductor laser epitaxial manufacturing method is to sequentially epitaxially generate an N-type material region, an active region, and a P-type material region on a substrate to form a double heterostructure. Features: When forming the double heterostructure by epitaxy, an etch stop layer is arranged in the P-type material region so that a P-type lower isolation layer and a P-type upper isolation layer are respectively formed under and above the etch stop layer; After forming a grating tunnel junction layer with a grating structure adjacent to the P-type upper isolation layer, coating a strip of photoresist on the grating tunnel junction layer; wherein the grating tunnel junction layer includes A heavily doped grating P-type layer and a heavily doped grating N-type layer, and the heavily doped grating P-type layer is adjacent to the P-type upper isolation layer, and the heavily doped grating N-type layer is adjacent to the heavily doped grating P-type layer layer; After etching down the grating tunnel junction layer and the P-type upper isolation layer not covering the strip photoresist and stopping at the etching stop layer to form a spine, remove the strip photoresist; wherein the active region has not been etched to reduce the luminous area; and After forming an N-type cladding layer and an N-type contact layer in sequence by one-time regrowth, an N-type metal electrode layer is arranged on the N-type contact layer; wherein the N-type cladding layer buries and covers the spine, the The N-type contact layer is disposed on the N-type cladding layer. The epitaxial manufacturing method as described in Claim 6, wherein the etching is anisotropic etching so that the grating tunnel junction layer of the spine is in the same range as the P-type upper isolation layer. A DFB semiconductor laser structure made by using the epitaxial manufacturing method described in any one of claims 6 and 7, characterized in that: in the DFB semiconductor laser structure, the substrate is epitaxially formed The active region is not etched to narrow the light-emitting range, so that the active region is larger than the spine, and the spine is the P-type upper isolation layer, the heavily doped grating P-type layer, and the heavily doped grating from bottom to top. Doped grating N-type layer. The DFB semiconductor laser structure according to claim 8, wherein the N-type material region sequentially includes a buffer layer, a first carrier gradient transition layer and a lower confinement layer from bottom to top, and the buffer layer is adjacent to the Substrate, the lower confinement layer is adjacent to the active region; the active region includes a lower graded layer, a lower energy barrier layer, an active layer, an upper energy barrier layer and an upper graded layer from bottom to top, and the lower graded layer Adjacent to the lower confinement layer, the upper graded layer is adjacent to the P-type material region; the P-type material region sequentially includes an upper confinement layer, the P-type lower isolation layer, the etch stop layer and the P-type upper an isolation layer, and the upper confinement layer is adjacent to the upper graded layer; and a second carrier graded transition layer and a third carrier graded layer are arranged between the N-type cladding layer and the N-type contact layer from bottom to top transition layer. The DFB semiconductor laser structure as described in Claim 9, wherein the substrate is made of InP material; the buffer layer is made of n-InP material, and the first carrier gradient transition layer is made of n-(Al _0.85 Ga _0.15 ) _0.47 In _0.53 As material and the lower confinement layer adopt n-In _0.53 Al _0.47 As material; the lower graded layer and the upper graded layer system adopt (Al _0.85 Ga _0.15 ) _0.47 In _0.53 As<->(Al _0.44 Ga _0.56 ) _0.47 In _0.53 As material, the lower energy barrier layer and the upper energy barrier layer adopt (Al _0.23 Ga _0.77 ) _0.52 In _0.48 As material and the active layer adopts (Al _0.22 Ga _0.78 ) _0.37 In _0.63 As material; the upper confinement layer system The p-In _0.53 Al _0.47 As material is used, the P-type lower isolation layer and the P-type upper isolation layer are made of p-InP material, and the etching stop layer is made of p-In _0.84 Ga _0.16 As _0.34 P _0.66 material; the grating passes through The tunnel interface layer is made of InGaAsP, AlGaInAs, InGaAs, AlInAs or InP material; the N-type cladding layer is made of InP material; the second carrier gradient transition layer is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material; the The third carrier gradient transition layer is made of n-In _0.61 Ga _0.39 As _0.84 P _0.16 material; and the n-type contact layer is made of n-In _0.53 Ga _0.47 As material. The DFB semiconductor laser structure as described in Claim 10, wherein the heavily doped grating P-type layer is made of p-In _0.71 Ga _0.29 As _0.62 P _0.38 material, and the heavily doped grating N-type layer is made of n-In _0.71 Ga _0.29 As _0.62 P _0.38 material.

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