低暗电流InAs/InAsSb II类应变超晶格红外探测材料的制备及相关基础研究

The minority carrier lifetime of InAs/GaSb II superlattice infrared detector due to defects of the GaSb material is very short, and limit the detector performance. InAs/InAsSb type II superlattice overcomes the drawback of InAs/GaSb superlattice, has a long minority carrier lifetime and low dark current. Firstly, MBE growth conditions of As-rich InAsSb films are studied in this project. So InAsSb thin films with controllable components, smooth surface and high crystal quality will be got. Then a new nBn minority carrier photo conductive infrared detector with low dark current will be prepared by InAs/InAsSb superlattice as the infrared absorption layer. By establishing the theoretical model, the effects of superlattice period, layer thickness, strain and other parameters on B/n band offset will be studied. Interface characteristic, behavior and carrier transport property of detector materials are researched. The influence mechanism of interface structure on carrier transport and dark current are revealed. Low defects growing mechanism of materials are studied. And we will explore device technology of low dark current InAs/InAsSb strain balanced superlattices IR detectors. Effect rule of different carrier transport principle of nBn and pin detectors on dark current and minority carrier lifetime will be researched.

InAs/GaSb II型超晶格红外探测器由于GaSb材料自身的缺陷导致其少子寿命很短，限制了探测器性能。InAs/InAsSb II型超晶格克服了InAs/GaSb 超晶格的缺点，具有长的少子寿命和极低的暗电流。本项目首先研究富As的InAsSb薄膜的MBE生长条件，得到组分可控、表面平整、具有高晶体质量的InAsSb薄膜材料。然后采用InAs/InAsSb超晶格作为红外光吸收层制备具有低暗电流的nBn型少子光导红外探测器。通过建立理论模型，研究超晶格周期、子层厚度、应变等参数对B/n带阶的影响规律；研究多层异质探测材料的界面特性、界面行为及载流子输运特性，揭示界面结构对载流子输运和暗电流的影响机理；开展失配体系多层异质探测材料的低缺陷生长机理研究，探索低暗电流InAs/InAsSb应变超晶格红外探测器的器件工艺。研究nBn与pin结构不同载流子输运机理对暗电流、少子寿命的影响规律。

本项目开展了InAs/InAsSb II类超晶格材料外延及红外探测器工艺的研究，重点进行了器件结构模拟、高性能材料制备、原型器件的研制、暗电流机理等方面的研究。经过系统的研究，我们得到以下重要结果：1）获得了低缺陷密度的InAs/InAsSb超晶格材料及优化生长条件；2）获得与衬底匹配的InAsSb和 InAs/InAsSb 超晶格材料，获得核心探测材料的制备参数；3）得到了适合InAs/InAsSb材料体系的器件工艺和钝化条件；4）明确暗电流机理和光电效率转换机理，实现器件关键技术的优化；5）同时开展了InAs/GaSb、InAs/InSb超晶格材料外延、器件工艺、原型器件制备及特性测试等工作，获得了性能良好的材料和器件。所获得的重要研究结果对进一步提高InAs/InAsSb II类超晶格及InAs/InSb、InAs/GaSb超晶格的器件质量，实现高性能红外焦平面探测器具有非常重要的意义。