TW466807B - Laser diode and method for fabricating the same - Google Patents

Abstract

A high output laser diode having an isolation structure and method for fabricating the same includes the steps of sequentially forming a first conductivity type clad layer, an active layer, a second conductivity type clad layer and a second conductivity type cap layer on a substrate, partially removing the second conductivity type cap layer, forming a dielectric layer on an entire surface including the second conductivity type cap layer and then partially removing the dielectric layer to expose the second conductivity type clad layer, etching the exposed second conductivity type clad layer and its below layers at a predetermined depth using the remaining dielectric layer as a mask, sequentially forming a second conductivity type current blocking layer and a first conductivity type current blocking layer on the exposed region, and removing the remaining dielectric layer to respectively form a metal layer on upper and lower parts of the substrate.

Description

466807 _ Case No. 88122231_ Office Year 彳 Month Buddhism Amendment _ V. Description of the invention (1) Background of the invention The field of invention of the present invention relates to a laser diode, especially a high power output with an isolation structure. Laser diode and method for manufacturing the same. Description of the background of the conventional technology Generally, a high-power laser diode includes a plurality of single devices on a wafer bank configured in an array configuration. The devices formed on the wafer lift are isolated from each other to avoid optical and electrical interference with adjacent devices. FIG. 1 is a partial view of a conventional laser diode array. As shown in Fig. 1, a first conductive type buffer layer 102, a first conductive type sheath layer 103, an active layer 104, and a second conductive type protective layer are sequentially formed on the first conductive type substrate 101 in this order. The cover layer 105 and the second conductive type cover layer 106. Etching the second conductive type cover layer and the first conductive type sheath layer in some parts, or etching the second conductive type cover layer and some parts of the substrate to form an isolation region. At this time, the isolation region is formed by implanting ions into the above-mentioned worm crystal layer. For implanting a required area, a dielectric layer such as Si 02 or Si NX is deposited on the second conductive type cover layer including the isolation region, and then a pattern is applied to expose a second conductive type cover layer. Part. Subsequently, a metal layer is deposited on the entire surface to form an electrode, thereby fabricating a laser diode array.

4 6 6 807 _Case No. 88122231_ and Year f Month and Day Amendment_ V. Description of the Invention (2) However, the above-mentioned conventional technology laser diode has certain problems. Because of its large thermal resistance and its deposition on the laser diode in the dielectric layer, it is difficult to remove the heat. This causes high temperatures to be generated on the laser diode, thereby deteriorating the performance of the laser diode and reducing its service life. At this point, a laser diode that can effectively remove heat is needed, so that it can perform high temperature and high power output operations. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a laser diode and a method for manufacturing the same, which can solve one or more problems caused by the limitations and disadvantages of the conventional technology. The object of the present invention is to provide a laser diode and a method for manufacturing the same. The use of the laser diode is suitable for high temperature and high power output operation without using a medium with poor thermal conductivity. Floor. Other features and advantages of the present invention will be described below. Part of this can be understood from the description or learned from the embodiments of the present invention. The purpose and advantages of the present invention can be understood and achieved from the description in the text, the scope of the patent application, and the structure specifically indicated in the drawings. In order to achieve the above-mentioned advantages and other advantages of the present invention, a method for manufacturing a laser diode is provided in the present invention. The method includes the following steps: sequentially forming a first conductive type protective layer on a substrate. A cover layer, an active layer, a second conductive type sheath layer, and a second conductive type cover layer; removing a part of the second conductive type cover layer; on the entire surface including the second conductive type cover layer Forming a dielectric layer, and partially

4 6 6 80 T Case No. 88122231 Amended on July 5, V. Description of the Invention (3) Remove a part of the dielectric layer to expose the second conductive type sheath layer; use the remaining dielectric layer as a photomask Etching the exposed second conductive type sheath layer to a predetermined depth below it; forming a second conductive type current blocking layer and a first conductive type current blocking layer in sequence in the exposed area; and removing the remaining dielectric The layers form a metal layer above and below the substrate, respectively. The band gaps of the materials forming the first and second conductivity type current blocking layers are smaller than the band gap of the light generated by the laser diode. In addition, the second conductive type current blocking layer is thicker than the active layer and is not in contact with the first and second conductive type sheath layers. In another design concept of the present invention, the present invention provides a laser diode having a plurality of unit laser diode devices. The laser diode includes: entering a corresponding laser diode device. A deep etched area; and a plurality of current layers with a certain thickness on the lower surface of the etched area for isolating corresponding laser diodes from each other. Those skilled in the art need to understand that the above description and the further description of the present invention below are examples and are used to explain the present invention, and the scope of patent application in the following further defines the present invention so that the reader Understand the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below, and these embodiments are shown in the drawings. The object of the present invention is to manufacture a laser diode, which makes the laser device isolated from each other by not using a dielectric layer having poor thermal conductivity.

466807 __Case No. 88122231_ Public year / month / c? Day Amendment_ V. Description of the invention (4) The emitter diode is suitable for high temperature and high pressure operation. 2A to 2G are partial views of manufacturing steps of a laser diode according to the present invention. As shown in FIG. 2A, a first conductive type buffer layer 2, a first conductive type sheath layer 3, an active layer 4, and a second conductive type sheath are sequentially formed on the first conductive type substrate 1 in order. Layer 5 and a second conductive type cover layer 6. Then, as shown in FIG. 2B, the second conductive type cover layer 6 is patterned by a photo-developing effect to form a plurality of stripe structures. Thereafter, the current flows only along the cover layer 6 of the strip, and laser oscillation occurs only under the cover layer 6. Subsequently, as shown in FIG. 2C, a dielectric layer 7 such as S i 0 2 or Si NX is deposited on the entire surface including the cover layer 6, and then a part of the dielectric layer 7 is removed by a tapeworm program, and The second conductive type sheath layer 5 is exposed. One or more strip-shaped covering layers or a unit laser diode device may be formed between the regions where the dielectric layer 7 is removed. As shown in FIG. 2E, the exposed second conductive type sheath layer 5 is etched using the remaining dielectric layer 7 as a photomask, and the active layer 4 and the first layer under the exposed second conductive type sheath layer Conductive type sheath layer 3. At this time, the substrate 1 of the first conductive type may be partially etched. Then, as shown in FIG. 2F, the second conductive type current blocking layer 8 and the first conductive type current blocking layer 9 are grown by the MOCVD process continuously in the etched area. At this time, the current blocking layers 8 and 9 do not grow in the area where the dielectric layer is formed, but grow in the #notch area. The material forming the current blocking layers 8 and 9 has a band gap smaller than the energy gap of the light generated by the laser diode. Therefore, the current blocking layer may have an optical isolation effect, and thus may absorb light. Moreover, the second conductive type current blocking layer 8 is higher than the first conductive type

Page 7 4 6 6 8 0 7 _Case No. 88122231_Amendment of your year and month Θ _ V. Description of the invention (5) The interface between the electrical type sheath layer 3 and the active layer 4, and at the same time lower than the first Interface between two conductive type sheath layer 5 and active layer 4. In other words, the thickness range of the second conductive type current blocking layer 8 can make the first conductive type current. The blocking layer 9 will not contact the first conductive type sheath layer, and the second conductive type current blocking layer 8 will not It is in contact with the second conductive type sheath layer 5. At the same time, the thickness of the first conductive type current blocking layer 9 has nothing to do with whether the second conductive type sheath layer 5 is in contact with the first conductive type current blocking layer 9 or not. Finally, as shown in Fig. 2G, the remaining dielectric layer 7 is completely removed, and then the metal layer 10 in ohmic contact with the second conductive type cover layer 6 is formed. The ohmic contact metal layer of the first conductive type substrate 1 is sequentially covered, deposited, and divided, so a laser diode array is manufactured. When manufacturing the above-mentioned laser diode, an etching region of a certain depth is formed in the corresponding unit device, and a first conductive type, a second conductive type, and a first conductive type are formed on a lower surface of the etched area. Current blocking layer of conductive type junction structure. Therefore, electrical and optical isolation can be achieved between the unit devices, and a dielectric layer having poor thermal conductivity is not required. As described above, the laser diode of the present invention and the method for manufacturing the laser diode have the following advantages: Because a dielectric layer can be used without the isolation procedure between devices, it is possible to apply a simple method suitable Laser diodes for high temperature and high output operation. Moreover, the use of the present invention to make all laser diode arrays requires an isolation procedure regardless of the specific material system used to make the laser diode. Obviously, those skilled in the art can apply the laser diode in the present invention.

Page 8 466807 _Case No. 88122231_ and year, month, and month P. Amendment _V. Description of the Invention (6) and the method for manufacturing the laser diode are modified and changed in many different ways without departing from the present invention. Spirit and perspective. Therefore, the scope of the present invention covers the scope of patent application, its meaning, and all modifications and changes.

466807 _Case No. 88122231_Year of the Month / Correction of Θ Days_ The diagrams following the explanatory text are intended to make the reader understand the invention and are included in the description of the invention as a part of this specification, and The embodiments of the present invention and the description thereof are for the reader to understand the principle of the present invention. In each figure, Fig. 1 illustrates a partial view of a conventional laser diode; and Figs. 2A to 2G illustrate partial views of manufacturing steps of a laser diode according to the present invention. Description of the drawing numbers 101 First conductive pattern base 102 First conductive pattern buffer layer 103 First conductive pattern sheath layer 104 Active layer 105 Second conductive pattern sheath layer 106 Second conductive pattern cover 107 Dielectric layer 108 Metal layer 1 First Conductive type substrate 2, 3 first conductive type buffer layer 4 active layer 5, 6th-conductive type sheath layer 7 dielectric layer 8, 9 current blocking layer

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Claims (1)

466807 _ Case No. 88122231_ This month, 0 months, 0 days_ charm_ 6. Application for patent scope 1. A method for manufacturing a laser diode, the method includes the following steps: sequentially forming on a substrate A first conductive type sheath layer, an active layer, a second conductive type sheath layer, and a second conductive type cover layer; removing a part of the second conductive type cover layer; including a second conductive type A dielectric layer is formed on the entire surface of the cover layer, and a part of the dielectric layer is partially removed to expose the second conductive type sheath layer. The remaining dielectric layer is used as a photomask to etch the exposed second layer. The conductive type sheath layer is a predetermined depth below it; a second conductive type current blocking layer and a first conductive type current blocking layer are sequentially formed in the exposed area; and the remaining dielectric layers are removed to be above the substrate, respectively. A metal layer is formed below. 2. The method for manufacturing a laser diode according to item 1 of the patent application scope, wherein the second conductive type covering layer has a plurality of strip-shaped structures. 3. The method for manufacturing a laser diode according to item 1 of the scope of patent application, wherein the energy band gap of the material forming the first and second conductive type current blocking layers is smaller than that generated by the laser diode Band gap of light. 4. The method for manufacturing a laser diode according to item 1 of the scope of patent application, wherein the second conductive type current blocking layer is thicker than the active layer and does not Page 11 466807 _ Case No. 88122231_ and Years and Months Γ ° said Amendment_ VI. Scope of patent application Contact with the first and second conductive type sheathing layer. 5. For the method for manufacturing a laser diode according to item 1 of the patent application scope, wherein the etching depth is a certain depth from the exposed second conductive type sheath layer to the first conductive type sheath layer, Or to a certain depth of the substrate. 6. A laser diode having a plurality of unit laser diode devices, the laser diode comprising: an etched region entering a certain depth of the corresponding laser diode device; and A plurality of current layers with a certain thickness on the lower surface are used to isolate corresponding laser diodes from each other. 7. For the laser diode of item 6 of the patent application, wherein the current layer has a different conductivity type. 8. The laser diode of item 6 of the patent application, wherein a plurality of unit laser diode devices are formed between the corresponding etched areas. Page 12