长波碲镉汞红外焦平面探测器暗电流机理分析
发布时间：2019-06-11 21:57
【摘要】：碲镉汞材料由于其可调的禁带宽度、电子迁移率高、较高的量子效率等优点在红外探测领域有非常重要的应用价值。碲镉汞的禁带宽度随着Cd组分变化可以从-0.3eV到1.6eV连续改变,在短波、中波和长波红外波段都有很好的响应率。尤其在长波红外波段,碲镉汞材料仍有很高的探测率,长波探测也是第三代高性能性能碲镉汞焦平面器件的主要目标。但是长波碲镉汞红外探测器由于材料有更窄的禁带宽度,良好的器件对材料生长、器件结构设计、流片工艺等有着更高的要求。长波碲镉汞器件的暗电流是制约红外探测器性能的主要原因,研究长波碲镉汞红外探测器暗电流机理是获取高性能长波碲镉汞红外探测器重要手段。基于实验测试数据,结合精细化数值分析模型和解析分析模型,本文对长波碲镉汞红外探测器暗电流成分分析和作用机理进行了研究。获取了不同结构、不同掺杂类型等探测器的暗电流成分,提取了关键物理参数,对长波碲镉汞的实验做出了指导,并能使精细化数值分析模型预测探测器性能。具体研究内容如下:1、对截止波长为9微米的P+-on-n双层组分异质结结构碲镉汞红外探测器暗电流成分进行了分析,通过解析模型研究两组不同n区掺杂浓度的器件发现,80K时器件在较大反偏条件下是辅助隧穿电流占主导,缺陷辅助隧穿电流远大于带间直接隧穿电流,直到器件零偏附近器件的暗电流才由产生复合电流占主导,器件在小正偏压下是扩散电流及串联电阻对电流有影响;分析获取不同温度下的特征参数发现,随着温度升高,器件的少子寿命越低,等效缺陷能级往价带位置移动;对比两种不同掺杂浓度的器件的特征参数发现,吸收层较高浓度的掺杂会导致缺陷增加,工艺上要追求更低掺杂浓度的方法。2、对截止波长为15微米的P+-on-n双层组分异质结结构甚长波碲镉汞红外探测器性能进行了分析,研究发现甚长波碲镉汞红外探测器对材料的缺陷、流片工艺等更加敏感。在大反偏时相同工艺的两批次器件均为隧穿电流占主导,小反偏时性能较好的器件是由产生复合电流占主导,而性能较差的器件是隧穿电流占主导,零偏附近时是与热激发相关的扩散电流和产生复合电流共同主导;随着温度的升高,能带逐渐变宽,带间隧穿电流逐渐降低,少子寿命逐渐降低,导致与热激发相关的电流逐渐增大,使器件暗电流增大;通过数值模型模拟得到Cd组分缓变层能带,认为Cd组分缓冲层厚度会是影响器件暗电流和探测率的重要因素;缺陷和位错的引入、Cd组分缓冲层造成的势垒高度的不同是导致焦平面器件性能不均一的重要因素。3、对截止波长为12.5微米的n-i-p结构Au与汞空位共同掺杂p型外延的碲镉汞红外探测器的性能进行了研究,首先建立了精细化数值分析模型,利用此模型对器件的暗电流分析此精细的数值分析模型在较大偏压时更能真实的反映器件的暗电流特性,与实验测试数据更加吻合;通过此模型,提取了不同p型掺杂浓度四个样品的暗电流成分,发现所有器件都是在大反偏下由带间隧穿电流主导,小反偏下是产生复合电流主导;随着掺杂浓度的增加,器件的SRH产生复合电流先增加后减小,器件的带间隧穿电流逐渐增大,通过仿真获取的少子寿命与其品质因子有非常好的正相关性,通过结区电场理论较好的分析了带间隧穿电流较大的原因;针对仿真获取少子寿命先增大后减小的物理现象,分析Au与汞空位的相互作用,认为少子寿命先增加是因为Au占据汞空位的原因,少子寿命减少是因为Au没有将Hg空位完全占据从而带来的缺陷的原因。
[Abstract]:Because of its tunable band gap, high electron mobility and high quantum efficiency, the mercury-bearing mercury material has very important application value in the field of infrared detection. The forbidden band width of the mercury is continuously changed from-0.3 eV to 1.6 eV with the change of Cd component, and there is a good response rate in the short-wave, medium-wave and long-wave infrared bands. In particular, in the long-wave infrared band, the high-performance mercury-containing material still has a high detection rate, and the long-wave detection is the main target of the third-generation high-performance and high-performance mercury-fired focal plane device. However, the long-wave mercury-sensitive infrared detector has higher requirements for material growth, device structure design, flow sheet process and so on due to the narrow band gap width of the material. The dark current of the long-wave mercury-sensitive mercury device is the main reason for restricting the performance of the infrared detector, and the dark current mechanism of the long-wave mercury-sensitive mercury infrared detector is an important means for obtaining the high-performance long-wave mercury-sensitive mercury infrared detector. Based on the experimental data, combined with the refined numerical model and the analytical model, this paper studies the dark current component analysis and the action mechanism of the long-wave mercury-mercury infrared detector. The dark current components of different structures, different doping types and the like are obtained, the key physical parameters are extracted, and the experimental results of the long-wave mercury-excited mercury are guided, and the fine numerical model can be used to predict the performance of the detector. The dark current component of a P +-on-n double-layer component heterostructure with a cut-off wavelength of 9 microns was analyzed, and the device discovery of different n-zone doping concentration was studied by means of the analytical model. when the device is 80K, the device is dominated by the auxiliary tunneling current under the condition of larger anti-bias, and the defect-assisted tunneling current is far greater than the direct tunneling current between the devices until the dark current of the device near the zero-bias of the device is dominated by the generation of the composite current, Under the bias of small positive bias, the diffusion current and the series resistance have an effect on the current; the characteristic parameters at different temperatures are analyzed to find that the lower sub-life of the device is lower, and the equivalent defect energy level moves to the valence band position as the temperature is increased; Comparing the characteristic parameters of the two devices with different doping concentration, the doping of the higher concentration of the absorption layer can lead to an increase of the defect, and the process of the process is to pursue the method of lower doping concentration. The performance of a P +-on-n double-layer component heterostructure with a cut-off wavelength of 15 microns was analyzed. the two-batch device of the same process is dominated by the tunneling current, and the device with good performance is dominated by the generation of the composite current, and the device with poor performance is dominated by the tunneling current, when the temperature increases, the energy band is gradually widened, the tunneling current is gradually reduced, and the sub-service life is gradually reduced, so that the current related to the thermal excitation is gradually increased, and the dark current of the device is increased; It is considered that the thickness of the buffer layer of the Cd component can be an important factor which can affect the dark current and the detection rate of the device. the difference of the barrier height caused by the cd component buffer layer is an important factor that leads to a non-uniform performance of the focal plane device.3, the performance of an n-i-p structure au with a cut-off wavelength of 12.5 microns and a mercury vacancy co-doped p-type epitaxial mercury-mercury infrared detector are studied, Firstly, a refined numerical analysis model is established, and the dark current of the device is analyzed by using the model, the dark current characteristic of the device can be more real reflected in the larger bias voltage, and the dark current characteristic of the device is more consistent with the experimental test data; and through the model, the dark current component of the four samples with different p-type doping concentration is extracted, The inter-band tunneling current of the device is gradually increased, the small sub-life obtained by the simulation has a very good positive correlation with the quality factor, the reason that the tunneling current is large is analyzed by the field theory of the junction region, and the physical phenomenon which is reduced after the small sub-life is first increased is obtained for the simulation, The interaction between Au and mercury vacancies is analyzed, and it is believed that the less sub-life is due to the fact that Au occupies the mercury vacancy, and the less sub-life is due to the fact that Au does not completely occupy the Hg vacancy.
【学位授予单位】：中国科学院大学(中国科学院上海技术物理研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN215
本文编号：2497482
[Abstract]:Because of its tunable band gap, high electron mobility and high quantum efficiency, the mercury-bearing mercury material has very important application value in the field of infrared detection. The forbidden band width of the mercury is continuously changed from-0.3 eV to 1.6 eV with the change of Cd component, and there is a good response rate in the short-wave, medium-wave and long-wave infrared bands. In particular, in the long-wave infrared band, the high-performance mercury-containing material still has a high detection rate, and the long-wave detection is the main target of the third-generation high-performance and high-performance mercury-fired focal plane device. However, the long-wave mercury-sensitive infrared detector has higher requirements for material growth, device structure design, flow sheet process and so on due to the narrow band gap width of the material. The dark current of the long-wave mercury-sensitive mercury device is the main reason for restricting the performance of the infrared detector, and the dark current mechanism of the long-wave mercury-sensitive mercury infrared detector is an important means for obtaining the high-performance long-wave mercury-sensitive mercury infrared detector. Based on the experimental data, combined with the refined numerical model and the analytical model, this paper studies the dark current component analysis and the action mechanism of the long-wave mercury-mercury infrared detector. The dark current components of different structures, different doping types and the like are obtained, the key physical parameters are extracted, and the experimental results of the long-wave mercury-excited mercury are guided, and the fine numerical model can be used to predict the performance of the detector. The dark current component of a P +-on-n double-layer component heterostructure with a cut-off wavelength of 9 microns was analyzed, and the device discovery of different n-zone doping concentration was studied by means of the analytical model. when the device is 80K, the device is dominated by the auxiliary tunneling current under the condition of larger anti-bias, and the defect-assisted tunneling current is far greater than the direct tunneling current between the devices until the dark current of the device near the zero-bias of the device is dominated by the generation of the composite current, Under the bias of small positive bias, the diffusion current and the series resistance have an effect on the current; the characteristic parameters at different temperatures are analyzed to find that the lower sub-life of the device is lower, and the equivalent defect energy level moves to the valence band position as the temperature is increased; Comparing the characteristic parameters of the two devices with different doping concentration, the doping of the higher concentration of the absorption layer can lead to an increase of the defect, and the process of the process is to pursue the method of lower doping concentration. The performance of a P +-on-n double-layer component heterostructure with a cut-off wavelength of 15 microns was analyzed. the two-batch device of the same process is dominated by the tunneling current, and the device with good performance is dominated by the generation of the composite current, and the device with poor performance is dominated by the tunneling current, when the temperature increases, the energy band is gradually widened, the tunneling current is gradually reduced, and the sub-service life is gradually reduced, so that the current related to the thermal excitation is gradually increased, and the dark current of the device is increased; It is considered that the thickness of the buffer layer of the Cd component can be an important factor which can affect the dark current and the detection rate of the device. the difference of the barrier height caused by the cd component buffer layer is an important factor that leads to a non-uniform performance of the focal plane device.3, the performance of an n-i-p structure au with a cut-off wavelength of 12.5 microns and a mercury vacancy co-doped p-type epitaxial mercury-mercury infrared detector are studied, Firstly, a refined numerical analysis model is established, and the dark current of the device is analyzed by using the model, the dark current characteristic of the device can be more real reflected in the larger bias voltage, and the dark current characteristic of the device is more consistent with the experimental test data; and through the model, the dark current component of the four samples with different p-type doping concentration is extracted, The inter-band tunneling current of the device is gradually increased, the small sub-life obtained by the simulation has a very good positive correlation with the quality factor, the reason that the tunneling current is large is analyzed by the field theory of the junction region, and the physical phenomenon which is reduced after the small sub-life is first increased is obtained for the simulation, The interaction between Au and mercury vacancies is analyzed, and it is believed that the less sub-life is due to the fact that Au occupies the mercury vacancy, and the less sub-life is due to the fact that Au does not completely occupy the Hg vacancy.
【学位授予单位】：中国科学院大学(中国科学院上海技术物理研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN215
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