GaAlAs红外发光二极管RTS噪声测试方法研究

针对GaAlAs红外发光二极管(IRLED) 随机电报信号(Random Telegraph Signal, RTS)噪声不易测量的特点,提出了一种自动温控RTS噪声测试新方法。通过分析GaAlAs IRLED的RTS噪声产生机理及特性,建立了GaAlAs IRLED的RTS噪声模型,对噪声测试的基本条件进行深入分析,并设计了自动温控测试系统。在10K的温度下对GaAlAs IRLED的RTS噪声进行测试,实验表明,该方法能准确的测量GaAlAs IRLED的RTS噪声,得到与噪声模型一致的结果,为GaAlAs IRLED可靠性的噪声表征提供了实验与理论依据。     

电应力对GaAlAs红外发光二极管低频噪声的影响

在宽范围偏置条件下,测量了电应力前后GaAlAs红外发光二极管（IRED）的低频噪声,发现应力前后1／f噪声随偏置电流变化的规律没有改变,但应力后1／f噪声幅值比应力前增加大约i00倍。基于载流子数和迁移率涨落的理论分析表明,GaAlAs IRED的1／f噪声在小电流时反映体陷阱特征,大电流时反映激活区陷阱特征,1／f噪声的增加归因于电应力在器件有源区诱生的界面陷阱和表面陷阱,因而,1／f噪声可以用来探测电应力对该类器件有源区的潜在损伤。     

GaAlAs红外发光二极管1/f噪声研究

在宽范围偏置条件下,测量了GaAlAs红外发光二极管（IRLED）的低频噪声,发现1／f噪声幅值与偏置电流If^γ的r次方成正比,在小电流区,r≈1。在大电流区r≈2。建立了一个GaAlAs IRLED的1／f噪声模型,得到与实验一致的定性结果。基于该模型的分析表明．低电流区GaAlAs IRLED的1／f噪声源于体陷阱对非平衡载流子俘获和发射导致的扩散电流涨落,高电流区的1／f噪声源于结空间电荷区附近氧化层陷阱对该处表面势的调制而引起载流子表面复合速率的涨落。该研究结果为1／厂噪声表征GaAlAs IRLED的可靠性提供了实验基础与理论依据。     

GaAlAs红外发光二极管功率老化对其1/f噪声特性的影响

在可靠性筛选中检测具有潜在损伤的器件一直是个难题.对GaA lAs红外发光二极管(IRLED)功率老化前后低频噪声的测量发现,1/f噪声幅值与偏置电流的γ次方成正比(小电流区γ=1,在大电流区γ≈2),且老化后1/f噪声幅值比老化前增大2个数量级.基于载流子数涨落和迁移率涨落机制建立了一个GaA lAs IR LED的1/f噪声模型,分析结果表明GaA lAs IR LED的1/f噪声在小电流时反映体陷阱特征,大电流时反映激活区陷阱特征,1/f噪声的增加归因于功率老化诱生的界面陷阱和表面陷阱,1/f噪声可以用来检测GaA lAs IR LED s的潜在缺陷.     

GaAlAs血红外发光二极管功率老化对其1/f噪声特性的影响

在可靠性筛选中检测具有潜在损伤的器件一直是个难题。对GaAlAs红外发光二极管（IRLED）功率老化前后低频噪声的测量发现，1／f噪声幅值与偏置电流的γ次方成正比（小电流区γ≈1，在大电流区γ≈2），且老化后1／f噪声幅值比老化前增大2个数量级。基于载流子数涨落和迁移率涨落机制建立了一个GaAlAs IR LED的1／f噪声模型，分析结果表明GaAlAs IR LED的1／f噪声在小电流时反映体陷阱特征，大电流时反映激活区陷阱特征，l／f噪声的增加归因于功率老化诱生的界面陷阱和表面陷阱，1／f噪声可以用来检测GaAlAs IR LEDs的潜在缺陷/     

两种钝化结构InGaAs红外探测器低频噪声的研究

低频噪声的测量和分析已成为红外探测器性能和可靠性评估的一种重要手段.制备了聚酰亚胺单层钝化和硫化后ZnS/聚酰亚胺双层钝化两种结构InGaAs探测器,测试了不同偏压或不同温度下器件的低频噪声谱,讨论了偏压和温度对InGaAs探测器低频噪声的影响.随着偏压的增加,噪声增大,拐点向低频方向移动,并且低频噪声随温度降低而减小.认为硫化后ZnS/聚酰亚胺双层钝化器件相对聚酰亚胺单层钝化器件相同偏压或温度下噪声较小,拐点低.因为硫化处理和ZnS层增强了钝化效果,器件的表面漏电流明显减小,因而大大降低了器件的低频噪声.     

新颖红外发光二极管

主要介绍近几年国外研制的红外正面、侧面发光二极管和超辐射发光二极管的最新进展，并对新开发的超晶格、量子阱发光二极管的基本结构、性能、制造技术和应用前景作了简要叙述。     

PbS红外探测器的低频噪声特性研究

PbS红外探测器的研究开始较早,由于其室温的优越性,至今应用仍很广泛.然而噪声严重影响了其性能,因此其噪声的研究目前很受重视.首先阐述了光导探测器的低频噪声理论;其次给出一简便而实用的PbS红外探测器低频噪声测量系统;最后在PbS红外探测器低频噪声实际测量和分析的基础上,分析了其低频噪声产生机理、偏压特性与温度特性,从而为改善器件质量提供了理论依据.     

发光二极管的低频电容特性

通过自建装置精确测试了发光二极管(LED)的低频(小于102Hz)电学特性。电学测量表明,所有LED在低频下都表现出明显的负电容(NC)现象,且频率越低NC现象越明显。调制发光测量表明,相对发光强度在低频下表现出明显饱和现象,并且随频率增加而减小。比较电学和光学的测量结果可以证实,辐射发光是产生NC现象的主要原因。通过对LED电学测量结果的详细分析得出了NC随电压和频率的变化关系式。     

Polarization-resolved low-frequency noise in GaAlAs lasers

Low-frequency intensity noise displaying 1/fdependency of the light polarized parallel and perpendicular to the junction plane and the correlation between these noise components is investigated in GaAlAs diode lasers. The absolute noise level for the component polarized parallel to the junction (lasing component) rises about 40 dB as the current passes through lasing threshold, while the noise for the orthogonal polarization drops by about 5 dB. The two noise components are well correlated slightly below threshold (coherence function ∼ 0.9), but the coherence function drops rapidly to near zero above threshold. An exception to this behavior occurs in the lasing mode when mode hopping takes place, when the two noise components are well correlated. A qualitative explanation for these phenomena is based on the relation between spontaneous and stimulated emission rates and fluctuations in the intracavity carrier density.     

Model for return-beam-induced noise generation in GaAlAs semiconductor lasers

The nature of the output intensity fluctuation noise generated when semiconductor lasers are irradiated by their own output beam are described. A possible explanation of their generation mechanism is presented utilising a simple rate equation model with an additional term accounting for the multiple reflections of the laser beam.     

FM noise of index-guided GaAlAs diode lasers

The FM-noise spectrum of index-guided GaAlAs-diode lasers is measured for different lengths of the laser cavity. The observed FM-noise peak near the internal laser resonance and the decrease of the FM noise with increasing cavity length is in agreement with a model which is considering the spontaneous emission noise source. From the measured noise data, the linewidth enhancement factor is determined.     

Consideration of low-frequency noise in MOSFETs for analogperformance

Low-frequency noise characteristics of MOSFETs have been studied in terms of their dependence on metal interconnect perimeter length, device W/L ratio, and gate-biasing voltage. In contrast to the theoretical model, a noise intensity increasing with lowering gate biasing was observed, which suggests that a compromise between noise performance and gain/offset voltage needs to be carefully examined in analog circuit design. Low-frequency noise was also found to be dependent on W/L ratio in devices with the same gate area, which should be considered in future device scaling     

Anomalies in transistor low-frequency noise

Accurate low-frequency noise measurements over the range of 1 Hz to 10 kHz on a number of different transistor types showed that the majority obey the f^-α-law, the factor α being between 0.96 and 1.23. Certain samples, however, exhibited an additional noise component with a frequency dependence of the form [1 + (f/f0)²]^-1.     

A low-frequency noise model for advanced gate-stack MOSFETs

A new unified noise model is presented that accurately predicts the low-frequency noise spectrum exhibited by MOSFETs with high dielectric constant (high-k), multi-stack gate dielectrics. The proposed multi-stack unified noise (MSUN) model is based on number and correlated mobility fluctuations theory developed for native oxide MOSFETs, and offers scalability with respect to the high-k/interfacial layer thicknesses. In addition, it incorporates the various electronic properties of high-k/interfacial layer materials such as energy barrier heights between different gate layers, and dielectric trap density with respect to band energy and position in the dielectric. For verification of the new model, the low-frequency noise, DC and conventional split C-V measurements were performed in the 78-350 K temperature range on TaSiN/HfO₂ n-channel MOSFETs. The interfacial layer in these devices was either thermal SiO₂ by Stress Relieved Pre-Oxide (SRPO) pretreatment or chemical SiO₂ resulting from standard RCA (Radio Corporation of America) clean process. Using the experimental noise data, the channel carrier number fluctuations mechanism was at first established to be the underlying mechanism responsible for the noise observed at all temperatures considered. Secondly, the normalized noise exhibited a weak dependence on temperature implying that the soft optical phonons, although known to result in mobility degradation, have no effect on the noise characteristics in these high-k gate stack MOSFETs. Finally, the new model was shown to be in excellent agreement with the measured noise in 1-100 Hz frequency range at temperatures of 78-350 K for both gate stacks.     

Interferometric measurement of low-frequency phase noise characteristics of diode laser-pumped Nd:YAG ring laser

Reports the interferometric measurement of the phase noise characteristics of a diode laser-pumped solid-state Nd:YAG 1.3 mu m laser based on a nonplanar ring cavity. Results show that the device has a low-frequency phase noise approximately three orders of magnitude lower than that observed with semiconductor diode lasers. The use of this source in fibre sensing applications is discussed.<>     

Coherence length and noise properties of GaAlAs broad-band sources

The coherence length of two types of GaAlAs broad-band sources have been measured as a function of current. The noise properties of these devices were also measured in short path-length difference interferometers.