INGAN/GAN MULTIPLE QUANTUM WELL BLUE LIGHT DETECTOR COMBINED WITH EMBEDDED ELECTRODE AND PASSIVATION LAYER STRUCTURE AND PREPARATION METHOD AND APPLICATION THEREOF

Abstract

An InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure and a preparation method and an application thereof are provided. The detector includes: a Si substrate, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer, an n-GaN buffer layer, an InGaN/GaN superlattice layer and an InGaN/GaN multiple quantum well layer in sequence from bottom to top. The multiple quantum well layer has a groove structure, a mesa and a groove of the multiple quantum well layer are provided with a Si.sub.3N.sub.4 passivation layer. The passivation layer in the groove is provided with a first metal layer electrode with a semicircular cross section, and the passivation layer on the mesa is provided with second metal layer electrode.

Claims

1. An InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure, comprising: a Si substrate, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer, an n-GaN buffer layer, an InGaN/GaN superlattice layer and an InGaN/GaN multiple quantum well layer in sequence from bottom to top, wherein the InGaN/GaN multiple quantum well layer has a groove structure, a mesa and a groove of the InGaN/GaN multiple quantum well layer are provided with a Si.sub.3N.sub.4 passivation layer, the Si.sub.3N.sub.4 passivation layer in the groove is provided with a first metal layer electrode with a semicircular cross section, and the Si.sub.3N.sub.4 passivation layer on the mesa is provided with a second metal layer electrode.

2. The InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the Si substrate has a thickness of 520 to 530 μm; the AlN/AlGaN/GaN buffer layer comprises an AlN layer with a thickness of 300-400 nm, an AlGaN layer with a thickness of 600-700 nm and a GaN layer with a thickness of 300-400 nm; the u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer comprises a first u-GaN layer with a thickness of 300-400 nm, an AlN layer with a thickness of 200-300 nm, a second u-GaN layer with a thickness of 300-400 nm, a SiN.sub.x layer with a thickness of 400-600 nm and a third u-GaN layer with a thickness of 300-400 nm; the n-GaN buffer layer has a thickness of 2-3 μm; the InGaN/GaN superlattice layer has a thickness of 500-600 nm and is in an alternating arrangement structure; the InGaN/GaN multiple quantum well layer has a thickness of 170-340 nm; and the Si.sub.3N.sub.4 passivation layer has a thickness of 5-20 nm.

3. The InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the first metal layer electrode and the second metal layer electrode are Ni/Au metal layer electrodes, the Ni/Au metal layer electrode comprising a Ni metal layer with a thickness of 70-90 nm and an Au metal layer with a thickness of 70-90 nm.

4. The InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the InGaN/GaN multiple quantum well layer is in a form of superimposing a layer of InGaN on a layer of GaN with superimposing for 9-12 times as a period, the GaN layer with a thickness of 13-18 nm, and the InGaN layer with a thickness of 6-10 nm.

5. The InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the first metal layer electrode and the second metal layer electrode are interdigital electrodes, the first metal layer electrode and the second metal layer electrodes being alternately arranged.

6. The InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the groove structure is a strip-shaped structure with equal spacing, the groove has a width of 100-150 nm and a depth of 160-200 nm, and a distance between center lines of two grooves is 400-650 nm; the first metal layer electrode is a semicircular electrode with a cross section radius of 100-140 nm; and an overall length-width dimension of the detector is 5.2×5.2 to 8.45×8.45 μm.sup.2.

7. A preparation method of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1, wherein the method comprises: step 1, growing an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer, an n-GaN buffer layer, an InGaN/GaN superlattice layer and an InGaN/GaN multiple quantum well layer on a Si substrate by MOCVD; step 2, performing ICP etching on the InGaN/GaN multiple quantum well layer obtained in step 1 to obtain a groove structure; step 3, performing PECVD to deposit a Si.sub.3N.sub.4 passivation layer on the InGaN/GaN multiple quantum well layer with the groove structure obtained in step 2; step 4, photoetching the Si.sub.3N.sub.4 passivation layer obtained in step 3 by firstly coating evenly and drying, then exposing and developing, and finally undergoing oxygen ion treatment; and step 5, evaporating the groove and the mesa of the Si.sub.3N.sub.4 passivation layer obtained in step 4, first evaporating Ni and then evaporating Au, after taking out, locally heating metal layer electrode by a resistance heating method to change a cross-sectional shape of the metal layer electrode to semicircle, and cleaning to obtain the InGaN/GaN multiple quantum well blue light detector.

8. The preparation method according to claim 7, wherein in step 2, the AlN/AlGaN/GaN buffer layer comprises an AlN layer grown at a temperature of 1000-1100° C., an AlGaN layer grown at a temperature of 1000-1100° C. and a GaN layer grown at a temperature of 900-1050° C.; the u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer comprises a first u-GaN layer grown at a temperature of 900-1050° C., an AlN layer grown at a temperature of 1000-1100° C., a second u-GaN layer grown at a temperature of 900-1050° C., a SiN.sub.x layer grown at a temperature of 1000-1100° C. and a third u-GaN layer grown at a temperature of 900-1050° C.; the n-GaN buffer layer is grown at a temperature of 900-1050° C.; and the InGaN/GaN superlattice layer and the InGaN/GaN multiple quantum well layer are grown at a temperature of 550-760° C.

9. The preparation method according to claim 7, wherein in step 4, a drying time is 35-48 s, an exposure time is 4-12 s, a developing time is 35-48 s, and an oxygen ion treatment time is 1.5-3.5 min; and in step 5, a rate of the evaporation is 0.16-0.22 nm/min, and a temperature of the heating is 1455-1555° C.

10. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 1 in blue light detection.

11. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 2 in blue light detection.

12. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 3 in blue light detection.

13. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 4 in blue light detection.

14. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 5 in blue light detection.

15. An application of the InGaN/GaN multiple quantum well blue light detector combined with embedded electrode and passivation layer structure according to claim 6 in blue light detection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 is a cross-sectional diagram of a partial interdigital electrode structure of an InGaN/GaN multiple quantum well (MQW) blue light detector of the present invention.

[0050] FIG. 2 is a schematic plan view of an electrode structure of the InGaN/GaN multiple quantum well (MQW) blue light detector of the present invention.

[0051] FIG. 3 is a PL curve of an InGaN/GaN multiple quantum well (MQW) blue light detector prepared in Embodiment 1.

[0052] FIG. 4 is a spectral response diagram of the InGaN/GaN multiple quantum well (MQW) blue light detector prepared in Embodiment 1.

DESCRIPTION OF THE EMBODIMENTS

[0053] The present invention will be described in further detail below in connection with embodiments, but the embodiments of the present invention are not limited thereto.

[0054] In a specific embodiment, the structural cross-sectional diagram of the InGaN/GaN multiple quantum well (MQW) blue light detector of the present invention is shown in FIG. 1. As can be seen from FIG. 1, from bottom to top, it successively includes a Si substrate 1, an AlN/AlGaN/GaN buffer layer 2, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer 3, an n-GaN buffer layer 4, an InGaN/GaN superlattice layer 5, an InGaN/GaN multiple quantum well layer 6 with a groove structure, a Si.sub.3N.sub.4 passivation layer 7, and a first Ni/Au metal layer electrode 8-1 and second Ni/Au metal layer electrode 8-2. The first Ni/Au metal layer electrode is located in the groove and the second Ni/Au metal layer electrodes are located on both sides of the planar groove, wherein the Si substrate 1 has a thickness of 520-530 μm; the AlN/AlGaN/GaN buffer layer 2 includes an AlN layer, an AlGaN layer and a GaN layer with thicknesses of 300-400 nm, 600-700 nm and 300-400 nm, respectively; the u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer 3 includes a u-GaN layer, an AlN layer, a u-GaN layer, a SiN.sub.x layer and a u-GaN layer with thicknesses of 300-400 nm, 200-300 nm, 300-400 nm, 400-600 nm and 300-400 nm, respectively; the n-GaN buffer layer 4 has a thickness of 2-3 μm; the InGaN/GaN superlattice layer 5 has a thickness of 500-600 nm; the InGaN/GaN MQW layer 6 has a thickness of 180-260 nm, and is in a form of superimposing a layer of InGaN on a layer of GaN with superimposing for 9-12 times as a period, the GaN layer has a thickness of 13-18 nm, and the InGaN layer has a thickness of 6-10 nm; the Si.sub.3N.sub.4 passivation layer 7 has a thickness of 5-20 nm; the Ni/Au metal layer electrode includes a Ni metal layer and an Au metal layer, the Ni metal layer has a thickness of 70-90 nm, and the Au metal layer has a thickness of 70-90 nm.

[0055] A schematic plan view of an electrode structure of the InGaN/GaN multiple quantum well (MQW) blue light detector of the present invention is shown in FIG. 2, the first metal layer electrode and the second metal layer electrodes are interdigital structure electrodes; the groove structure is a strip-shaped structure with equal spacing, the groove has a width of 100-150 nm and a depth of 160-200 nm, and a distance between center lines of two grooves is 400-650 nm, and a radius of the semicircular electrode is about 100-140 nm; and an overall size of the detector is 5.2×5.2 to 8.45×8.45 μm.sup.2.

Embodiment 1

[0056] The InGaN/GaN multiple quantum well (MQW) blue light detector and the preparation method thereof of the embodiment include the following steps.

[0057] (1) Firstly, according to the structure design, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and an n-GaN buffer layer are grown at high temperature on a Si substrate by MOCVD at temperatures of 1000° C., 1000° C., 900° C., 900° C., 1000° C., 900° C., 1000° C., 900° C. and 900° C., respectively. The thin film thicknesses of the AlN/AlGaN/GaN buffer layer, u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and n-GaN buffer layer are 300 nm, 600 nm, 300 nm, 400 nm, 300 nm, 400 nm, 400 nm, 400 nm and 2 μm, respectively. Secondly, the InGaN/GaN superlattice layer and the InGaN/GaN multiple quantum well layer are grown by MOCVD at a temperature of 600° C. The InGaN/GaN superlattice layer is composed of InGaN and GaN alternately arranged for 10 periods, in each period, the GaN layer has a thickness of 48 nm and the InGaN layer has a thickness of 12 nm, and a total thickness is 600 nm. The InGaN/GaN multiple quantum well layer has 11 periods in total, and the MQW has a thickness of 220 nm, in which the GaN layer has a thickness of 13 nm and InGaN layer has a thickness of 7 nm.

[0058] (2) According to the electrode design, the InGaN/GaN multiple quantum well layer obtained in step (1) is etched by ICP to obtain a square wave groove structure with a depth of 180 nm and a width of 100 nm. A distance between the center lines of the two grooves is 400 nm, and a radius of the semicircular electrode is about 107 nm.

[0059] (3) According to the electrode design, the InGaN/GaN multiple quantum well layer with a groove structure obtained in step (2) is subjected to PECVD to deposit a Si.sub.3N.sub.4 passivation layer with a thickness of 10 nm.

[0060] (4) According to the electrode design, the Si.sub.3N.sub.4 passivation layer obtained in step (3) is photoetched by coating a sample evenly first, drying for 38 s, then exposing for 6 s, developing for 38 s, and finally treating with oxygen ion for 2.5 min.

[0061] (5) According to the electrode design, the Si.sub.3N.sub.4 passivation layer obtained in step (4) is evaporated, the evaporation rate is controlled to be 0.17 nm/min, Ni and Au are evaporated for 70 nm sequentially, and a groove evaporation electrode is used as an anode and a mesa evaporation electrode is used as a cathode. After taking out and cleaning, the InGaN/GaN multiple quantum well (MQW) blue light detector is obtained.

[0062] (6) The InGaN/GaN multiple quantum well (MQW) blue light detector obtained in step (5) is tested.

[0063] As shown in FIG. 1, the InGaN/GaN multiple quantum well (MQW) blue light detector prepared by this embodiment, includes the Si substrate 1, the AlN/AlGaN/GaN buffer layer 2 grown on the Si substrate 1, the u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer 3 grown on the AlN/AlGaN/GaN buffer layer 2, the n-GaN buffer layer 4 grown on the u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer 3, the InGaN/GaN superlattice layer 5 grown on the n-GaN buffer layer 4, the InGaN/GaN multiple quantum well layer 6 grown on the InGaN/GaN superlattice layer 5, the Si.sub.3N.sub.4 passivation layer 7 grown on the InGaN/GaN multiple quantum well layer 6, and the first Ni/Au metal layer electrode 8-1 and second Ni/Au metal layer electrode 8-2 grown on the Si.sub.3N.sub.4 passivation layer 7.

[0064] FIG. 2 is a schematic plan view of a structure of the InGaN/GaN multiple quantum well (MQW) blue light detector of the present invention.

[0065] FIGS. 3 and 4 are a PL curve and a photocurrent curve measured by the InGaN/GaN multiple quantum well (MQW) blue light detector obtained in this embodiment. It can be seen from the curves that the detector has extremely high bandwidth and high responsivity of 0.74 A/W in blue band.

Embodiment 2

[0066] The InGaN/GaN multiple quantum well (MQW) blue light detector and the preparation method thereof of the embodiment include the following steps.

[0067] (1) Firstly, according to the structure design, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and an n-GaN buffer layer are grown at high temperature on a Si substrate by MOCVD at temperatures of 1050° C., 1050° C., 950° C., 950° C., 1050° C., 950° C., 1050° C., 950° C. and 950° C., respectively. The thin film thicknesses of the AlN/AlGaN/GaN buffer layer, u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and n-GaN buffer layer are 350 nm, 650 nm, 350 nm, 300 nm, 200 nm, 300 nm, 600 nm, 300 nm, 2.5 μm, respectively. Secondly, the InGaN/GaN superlattice layer and the InGaN/GaN multiple quantum well layer are grown by MOCVD at a temperature of 750° C. The InGaN/GaN superlattice layer is composed of InGaN and GaN alternately arranged for 10 periods, in each period, the GaN layer has a thickness of 40 nm and the InGaN layer has a thickness of 10 nm, and a total thickness is 500 nm. The InGaN/GaN multiple quantum well layer has 12 periods in total, and the MQW has a thickness of 240 nm, in which the GaN layer has a thickness of 14 nm and InGaN layer has a thickness of 6 nm.

[0068] (2) According to the electrode design, the InGaN/GaN multiple quantum well layer obtained in step (1) is etched by ICP to obtain a square wave groove structure with a depth of 190 nm and a width of 150 nm. A distance between the center lines of the two grooves is 450 nm, and a radius of the semicircular electrode is about 135 nm.

[0069] (3) According to the electrode design, the InGaN/GaN multiple quantum well layer with a groove structure obtained in step (2) is subjected to PECVD to deposit a Si.sub.3N.sub.4 passivation layer with a thickness of 15 nm.

[0070] (4) According to the electrode design, the InGaN/GaN multiple quantum well layer for covering the passivation layer obtained in step (3) is photoetched by coating a sample evenly first, drying for 42 s, then exposing for 8 s, developing for 42 s, and finally treating with oxygen ion for 2 min.

[0071] (5) According to the electrode design, the Si.sub.3N.sub.4 passivation layer obtained in step (4) is evaporated, the evaporation rate is controlled to be 0.19 nm/min, Ni and Au are evaporated for 80 nm sequentially, and a groove evaporation electrode is used as an anode and a mesa evaporation electrode is used as a cathode. After taking out and cleaning, the InGaN/GaN multiple quantum well (MQW) blue light detector is obtained.

[0072] (6) The InGaN/GaN multiple quantum well (MQW) blue light detector obtained in step (5) is tested.

[0073] The InGaN/GaN Multiple Quantum Well (MQW) blue light detector prepared in this embodiment has an effect similar to that of Embodiment 1 and will not be described here.

Embodiment 3

[0074] The InGaN/GaN multiple quantum well (MQW) blue light detector and the preparation method thereof of the embodiment include the following steps:

[0075] (1) Firstly, according to the structure design, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and an n-GaN buffer layer are grown at high temperature on a Si substrate by MOCVD at temperatures of 1100° C., 1100° C., 1000° C., 1000° C., 1100° C., 1000° C., 1100° C., 1000° C., 1000° C., respectively. The thin film thicknesses of the AlN/AlGaN/GaN buffer layer, u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and n-GaN buffer layer are 400 nm, 700 nm, 400 nm, 350 nm, 250 nm, 350 nm, 500 nm, 350 nm, 3 μm, respectively. Secondly, the InGaN/GaN superlattice layer and the InGaN/GaN multiple quantum well layer are grown by MOCVD at a temperature of 750° C. The InGaN/GaN superlattice layer is composed of InGaN and GaN alternately arranged for 10 periods, in each period, the GaN layer has a thickness of 42 nm and the InGaN layer has a thickness of 10 nm, and a total thickness is 520 nm. The InGaN/GaN multiple quantum well layer has 13 periods in total, and the MQW has a thickness of 260 nm, in which the GaN layer has a thickness of 14 nm and InGaN layer has a thickness of 6 nm.

[0076] (2) According to the electrode design, the InGaN/GaN multiple quantum well layer obtained in step (1) is etched by ICP to obtain a square wave groove structure with a depth of 200 nm and a width of 120 nm. A distance between the center lines of the two grooves is 420 nm, and a radius of the semicircular electrode is about 125 nm.

[0077] (3) According to the electrode design, the InGaN/GaN multiple quantum well layer with a groove structure obtained in step (2) is subjected to PECVD to deposit a Si.sub.3N.sub.4 passivation layer with a thickness of 12 nm.

[0078] (4) According to the electrode design, the InGaN/GaN multiple quantum well layer for covering the passivation layer obtained in step (3) is photoetched by coating a sample evenly first, drying for 45 s, then exposing for 9 s, developing for 45 s, and finally treating with oxygen ion for 3 min.

[0079] (5) According to the electrode design, the Si.sub.3N.sub.4 passivation layer obtained in step (4) is evaporated, the evaporation rate is controlled to be 0.21 nm/min, Ni and Au are evaporated for 90 nm sequentially, and a groove evaporation electrode is used as an anode and a mesa evaporation electrode is used as a cathode. After taking out and cleaning, the InGaN/GaN multiple quantum well (MQW) blue light detector was obtained.

[0080] (6) The InGaN/GaN multiple quantum well (MQW) blue light detector obtained in step (5) is tested.

[0081] The InGaN/GaN Multiple Quantum Well (MQW) blue light detector prepared in this embodiment has an effect similar to that of Embodiment 1 and will not be described here.

Embodiment 4

[0082] The InGaN/GaN multiple quantum well (MQW) blue light detector and the preparation method thereof of the embodiment include the following steps.

[0083] (1) Firstly, according to the structure design, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and an n-GaN buffer layer are grown at high temperature on a Si substrate by MOCVD at temperatures of 1075° C., 1075° C., 975° C., 975° C., 1075° C., 975° C., 1075° C., 975° C., 975° C., respectively. The thin film thicknesses of the AlN/AlGaN/GaN buffer layer, u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer and n-GaN buffer layer are 375 nm, 675 nm, 375 nm, 325 nm, 225 nm, 325 nm, 625 nm, 325 nm, 2.75 μm, respectively. Secondly, the InGaN/GaN superlattice layer and the InGaN/GaN multiple quantum well layer are grown by MOCVD at a temperature of 750° C. The InGaN/GaN superlattice layer is composed of InGaN and GaN alternately arranged for 10 periods, in each period, the GaN layer has a thickness of 44 nm and the InGaN layer has a thickness of 11 nm, and a total thickness is 550 nm. The InGaN/GaN multiple quantum well layer has 9 periods in total, and the MQW has a thickness of 180 nm, in which the GaN layer has a thickness of 14 nm and InGaN layer has a thickness of 6 nm.

[0084] (2) According to the electrode design, the InGaN/GaN multiple quantum well layer obtained in step (1) is etched by ICP to obtain a square wave groove structure with a depth of 170 nm and a width of 130 nm. A distance between the center lines of the two grooves is 500 nm, and a radius of the semicircular electrode is about 120 nm.

[0085] (3) According to the electrode design, the InGaN/GaN multiple quantum well layer with a groove structure obtained in step (2) is subjected to PECVD to deposit a Si.sub.3N.sub.4 passivation layer with a thickness of 11 nm.

[0086] (4) According to the electrode design, the InGaN/GaN multiple quantum well layer for covering the passivation layer obtained in step (3) is photoetched by coating a sample evenly first, drying for 43 s, then exposing for 9 s, developing for 43 s, and finally treating with oxygen ion for 2 min.

[0087] (5) According to the electrode design, the Si.sub.3N.sub.4 passivation layer obtained in step (4) is evaporated, the evaporation rate is controlled to be 0.18 nm/min, Ni and Au are evaporated for 85 nm sequentially, and a groove evaporation electrode is used as an anode and a mesa evaporation electrode is used as a cathode. After taking out and cleaning, the InGaN/GaN multiple quantum well (MQW) blue light detector was obtained.

[0088] (6) The InGaN/GaN multiple quantum well (MQW) blue light detector obtained in step (5) is tested.

[0089] The InGaN/GaN Multiple Quantum Well (MQW) blue light detector prepared in this embodiment has an effect similar to that of Embodiment 1 and will not be described here.

[0090] The above embodiments are preferred embodiments of the present invention, but the implementation of the present invention is not limited by the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be equivalence and are encompassed in the protection scope of the present invention.