CN109300853B - 一种新型发光二极管量子阱及其制备方法 - Google Patents

一种新型发光二极管量子阱及其制备方法 Download PDF

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CN109300853B
CN109300853B CN201811022466.6A CN201811022466A CN109300853B CN 109300853 B CN109300853 B CN 109300853B CN 201811022466 A CN201811022466 A CN 201811022466A CN 109300853 B CN109300853 B CN 109300853B
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孙旭东
祝光辉
任亮亮
曾海军
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Huaian Aucksun Optoelectronics Technology Co Ltd
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Abstract

本发明属于半导体技术领域,提供了一种新型发光二极管量子阱及制备方法,包括蓝宝石衬底以及依次层叠在蓝宝石衬底上的缓冲层、未掺杂氮化镓层、n型氮化镓层、应力释放层、多量子阱结构以及p型氮化镓层;所述多量子阱结构包括5~15个周期量子阱结构单元,每个量子阱结构单元包括纯氮气环境生长的铟镓氮量子阱区、纯氮气环境生长的AlxGa1‑xN Cap区以及纯氢气环境生长的AlmGa1‑mN量子垒区。本发明纯氮气环境生长的铟镓氮量子阱区与AlxGa1‑xN Cap区,得到铟组分掺杂良好的铟镓氮量子阱区。纯氢气环境下生长的AlmGa1‑mN量子垒区,生长缺陷少,晶体质量得到改善。

Description

一种新型发光二极管量子阱及其制备方法
技术领域
本发明属于半导体技术领域,涉及一种新型发光二极管量子阱及其制备方法。
背景技术
现有的发光二极管(LED)外延片结构包括图形化蓝宝石衬底以及依次层叠在衬底上的缓冲层、未掺杂氮化镓层、n型氮化镓层、应力释放层、多量子阱结构以及p型氮化镓层。多量子阱结构是由700~800℃温度下生长的铟镓氮(InGaN)量子阱区、保护铟组分均匀分布与获得清晰量子阱垒界面的Cap区以及800~900℃温度下生长的量子垒区组成的超晶格单元重复构成。
多量子阱结构作为LED中电子和空穴辐射复合发光的位置,直接决定着辐射复合发光的波长和强度,是LED发光的核心结构,因此制备高质量的多量子阱结构是实现高亮度、高效率发光LED的关键。然而铟镓氮体系多量子阱结构的优化生长迄今面临着许多困难。首先,氮化铟晶体与氮化镓晶体之间的晶格失配高达11%,导致铟镓氮/氮化镓多量子阱晶体质量偏差,存在大量的位错。其次,铟镓氮/氮化镓多量子阱中的应力引起极化效应,产生量子限制斯塔克效应(QCSE),造成LED内量子效率降低。第三,铟镓氮/氮化镓多量子阱对生长气氛具有选择性,氮气环境有利于量子阱铟组分的掺入,但生长缺陷较多;氢气环境可以显著提高氮化镓的晶体质量,却不利于量子阱区中铟组分的掺入。
发明内容
为改善现有铟镓氮/氮化镓多量子阱结构的生长技术,本发明提出一种新型发光二极管量子阱结构与生长方式。
一种新型发光二极管量子阱,如图1所示,包括蓝宝石衬底以及依次层叠在蓝宝石衬底上的缓冲层、未掺杂氮化镓层、n型氮化镓层、应力释放层、多量子阱结构以及p型氮化镓层;所述多量子阱结构包括5~15个周期量子阱结构单元,每个量子阱结构单元包括纯氮气环境生长的铟镓氮量子阱区、纯氮气环境生长的AlxGa1-xN Cap区以及纯氢气环境生长的AlmGa1-mN量子垒区;
所述的铟镓氮量子阱区的生长厚度为3~5nm;
所述的AlxGa1-xN Cap区的生长厚度为0.5~2nm,其中0<x≦0.3;
所述的AlmGa1-mN量子垒区生长厚度为5~15nm,其中0.2≦m≦0.6;
所述的AlxGa1-xN Cap区与AlmGa1-mN量子垒区,均掺入硅烷;
所述的纯氮气环境生长的铟镓氮量子阱区,采用纯氮气作为反应室气氛与载气气氛,包括三乙基镓(TEGa)源、三甲基铟(TMIn)源以及氨气(NH3)源都是纯氮气载气,完全避免该生长阶段中氢气气氛的引入,获得量子阱铟组分的良好掺入。
所述纯氮气环境生长的AlxGa1-xN Cap区,采用纯氮气作为反应室气氛与载气气氛,包括三甲基铝(TMAl)源、三乙基镓(TEGa)源、硅烷源以及氨气(NH3) 源都是纯氮气载气,不仅保持了铟镓氮量子阱区的氮气环境,还能够阻隔量子阱中的缺陷,而且AlxGa1-xN禁带宽度更大,能够更好的束缚电子于量子阱区中。
所述纯氢气环境生长的AlmGa1-mN量子垒区,采用纯氢气作为反应室气氛与载气气氛,包括三甲基铝(TMAl)源、三乙基镓(TEGa)、硅烷源以及氨气 (NH3)源都是纯氢气载气,可以显著提高量子垒的晶体质量。
所述多量子阱结构生长的Ⅴ/Ⅲ比为5000~50000,其中Ⅴ/Ⅲ比为V族氮原子和Ⅲ族镓原子之和与铟原子和铝原子之和的摩尔比。具体地,当生长铟镓氮量子阱区时,Ⅴ/Ⅲ比为氮原子,与镓原子和铟原子之和的摩尔比;当生长AlxGa1-xN Cap区时,Ⅴ/Ⅲ比为氮原子,与镓原子和铝原子之和的摩尔比;当生长AlmGa1-mN量子垒区时,Ⅴ/Ⅲ比为氮原子,与镓原子和铝原子之和的摩尔比。
一种新型发光二极管量子阱的制备方法,步骤如下:
步骤1:提供一蓝宝石衬底;
步骤2:在蓝宝石衬底上依次生长缓冲层、未掺杂氮化镓层、n型氮化镓层和应力释放层;
步骤3:生长完应力释放层后,开始生长多量子阱结构,设置反应室压力为200~600mbar,设置Ⅴ/Ⅲ比为5000~50000。先采用纯氮气作为反应室气氛与载气气氛,打开三乙基镓源、三甲基铟源以及氨气源,在700~800℃生长铟镓氮量子阱区,控制厚度为3~5nm;
步骤4:保持量子阱生长温度,打开三甲基铝源、三乙基镓源、硅烷源以及氨气源,然后生长AlxGa1-xN Cap区,控制厚度为0.5~2nm;
步骤5:切换纯氢气作为反应室气氛与载气气氛,打开三甲基铝源、三乙基镓源、硅烷源以及氨气源,生长AlmGa1-mN量子垒区,控制厚度为 5~15nm,生长温度为800~900℃;
步骤6:重复步骤3、4和5共5~15次,即生长5~15个量子阱单层结构单元;
步骤7:生长完多量子阱结构后继续生长p型氮化镓层。
本发明的有益效果是:本发明创新在于提供了一种新型发光二极管多量子阱结构,并提出了一种有效而简便的工艺制造技术与装置。本发明纯氮气环境生长的铟镓氮量子阱区与AlxGa1-xN Cap区,得到铟组分掺杂良好的铟镓氮量子阱区。纯氢气环境下生长的AlmGa1-mN量子垒区,生长缺陷少,晶体质量得到改善。此外相比于传统氮化镓Cap层与量子垒层,铝镓氮Cap层与量子垒层还能够阻隔缺陷,而且禁带宽度更大,能够更好的束缚电子于量子阱区中,增加了电子与空穴复合的几率。
附图说明
图1是本发明的外延结构示意图。
图2是本发明的多量子阱结构中一个单元示意图,是图1中6的单元结构。
图中:1蓝宝石衬底;2缓冲层;3未掺杂氮化镓层;4n型氮化镓层;5应力释放层;6多量子阱结构;7p型氮化镓层;6.1第一层量子阱单层结构单元; 6.2第二层量子阱单层结构单元;6.3第三层量子阱单层结构单元。
具体实施方式
以下结合技术方案和附图,进一步说明本发明的具体实施方式。
实施例1
一种新型发光二极管量子阱的制备方法,包括以下工艺步骤:
反应源与载气:提供两瓶三甲基铝源、提供两瓶三乙基镓源,其中一瓶三甲基铝源与三乙基镓源用氢气作为载气,标记为三甲基铝1源与三乙基镓1源,另一瓶三甲基铝源与三乙基镓源用氮气作为载气,标记为三甲基铝2 源与三乙基镓2源;氮气作为三甲基铟(TMIn)源的载气,硅烷(SiH4)提供n型掺杂,载气气氛为氢气与氮气可切换,二茂镁(CP2Mg)提供p型掺杂,氨气(NH3)作为Ⅴ族源,TEGa、TMAl、TMIn作为Ⅲ族有机金属源。
步骤1:参见图1,提供一蓝宝石衬底1;
步骤2:在衬底1上依次生长缓冲层2、未掺杂氮化镓层3、n型氮化镓层4、应力释放层5;
步骤3:长完应力释放层5后准备生长多量子阱结构6时,设置反应室压力为300mbar,设置Ⅴ/Ⅲ比为30000,切换纯氮气作为反应室气氛与反应源载气,打开三乙基镓2源、三甲基铟源以及氨气源,在量子阱生长温度750 ℃下反应生长InGaN量子阱(6.1),量子阱厚度为4nm;
步骤4:保持750℃,保持氮气作为反应室气氛与反应源载气,打开三甲基铝2源、三乙基镓2源、硅烷源与氨气源,生长Al0.1Ga0.9N Cap层(6.2), Cap层厚度为1nm;
步骤5:切换反应室气氛与反应源载气为氢气气氛,打开三甲基铝1源、三乙基镓1源、硅烷源与氨气源,在量子垒生长温度850℃下生长Al0.3Ga0.7N 量子垒层(6.3),量子垒厚度为8nm;
步骤6:依次生长步骤3、步骤4、步骤5共10个循环;
步骤7:在长完多量子阱结构6后继续生长p型氮化镓层7。
最后应说明的是:以上各实施例仅用以说明本发明的技术方案,而非对其限制;尽管参照前述各实施例对本发明进行了详细的说明,本领域的普通技术人员应当理解:其依然可以对前述各实施例所记载的技术方案进行修改,或者对其中部分或者全部技术特征进行等同替换;而这些修改或者替换,并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (3)

1.一种发光二极管,其特征在于,所述的发光二极管包括蓝宝石衬底以及依次层叠在蓝宝石衬底上的缓冲层、未掺杂氮化镓层、n型氮化镓层、应力释放层、多量子阱结构以及p型氮化镓层;所述多量子阱结构包括5~15个周期量子阱结构单元,每个量子阱结构单元包括反应室气氛与载气气氛为纯氮气环境生长的铟镓氮量子阱区、反应室气氛与载气气氛纯氮气环境生长的AlxGa1-xN Cap区以及反应室气氛与载气气氛纯氢气环境生长的AlmGa1-mN量子垒区;
所述的铟镓氮量子阱区的生长厚度为3~5nm;
所述的AlxGa1-xN Cap区的生长厚度为0.5~2nm,其中0<x≦0.3;
所述的AlmGa1-mN量子垒区生长厚度为5~15nm,其中0.2≦m≦0.6;
所述的AlxGa1-xN Cap区与AlmGa1-mN量子垒区,均掺入硅烷。
2.根据权利要求1所述的发光二极管,其特征在于,所述的多量子阱结构生长的Ⅴ/Ⅲ比为5000~50000,Ⅴ/Ⅲ比为V族氮原子与Ⅲ族镓原子之和、铟原子和铝原子之和的摩尔比;当生长铟镓氮量子阱区时,Ⅴ/Ⅲ比为氮原子、与镓原子和铟原子之和的摩尔比;当生长AlxGa1-xN Cap区时,Ⅴ/Ⅲ比为氮原子、与镓原子和铝原子之和的摩尔比;当生长AlmGa1-mN量子垒区时,Ⅴ/Ⅲ比为氮原子、与镓原子和铝原子之和的摩尔比。
3.一种发光二极管的制备方法,其特征在于,步骤如下:
步骤1:提供一蓝宝石衬底;
步骤2:在蓝宝石衬底上依次生长缓冲层、未掺杂氮化镓层、n型氮化镓层和应力释放层;
步骤3:生长完应力释放层后,开始生长多量子阱结构,设置反应室压力为200~600mbar,设置Ⅴ/Ⅲ比为5000~50000;先采用纯氮气作为反应室气氛与载气气氛,打开三乙基镓源、三甲基铟源以及氨气源,在700~800℃生长铟镓氮量子阱区,控制厚度为3~5nm;
步骤4:保持量子阱结构生长温度,打开三甲基铝源、三乙基镓源、硅烷源以及氨气源,然后生长AlxGa1-xN Cap区,控制厚度为0.5~2nm,其中0<x≦0.3;
步骤5:切换纯氢气作为反应室气氛与载气气氛,打开三甲基铝源、三乙基镓源、硅烷源以及氨气源,生长AlmGa1-mN量子垒区,控制厚度为5~15nm,生长温度为800~900℃,其中0.2≦m≦0.6;
步骤6:重复步骤3、4和5共5~15次,即生长5~15个量子阱单层结构单元;
步骤7:生长完多量子阱结构后继续生长p型氮化镓层。
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