【作者】 李靖；

【导师】 石家纬；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2004， 硕士

【摘要】 随着高新技术的发展，半导体激光器作为一种重要光源，在光纤通信、光传感、信息存储，医疗以及泵浦固体激光器和光纤放大器等领域得到广泛应用。半导体激光器的质量和可靠性在应用系统中起着关键作用，因此，半导体激光器的可靠性及其规律的研究对于改善其性能有着重要意义。目前对半导体激光器质量检测和可靠性筛选的方法通常是采用电老化的方法，它是把一定电流下输出光功率变化率或一定输出功率下所加驱动电流变化率大的器件筛选掉，按照变化率大小把器件的可靠性分档。这种方法得到的是一种统计结果，耗时长。在电老化过程中，好的器件也要经受到热、电冲击，影响使用寿命。在长时间电老化过程中如果遇到系统失控或停电等意外情况，会使器件成批损坏，损失将是严重的。而且电老化对器件中的潜在缺陷不敏感。表现为：电老化筛选认为合格的器件在使用过程中也会发生快速失效。因此，寻求一种新的、快捷、有效且无损的方法进行器件检测和可靠性评价是一件很有实际意义的工作。半导体激光器在工作时，其两端的pn结电压会出现随机涨落，称为电噪声。电噪声反映了材料或器件的不完整性，对影响器件可靠性的潜在缺陷比器件的其他参数要敏感。噪声测试可以对单个器件的质量和可靠性做出评价，噪声测试时若加在器件两端的电压或流过的电流，接近或低于器件正常的应力水平，对器件没有破坏性。因此，将快速、敏感、无损的噪声分析方法应用于半导体激光器的质量检测和可靠性筛选，对于研制、生产和使用器件是十分有意义的。本文首先综述了半导体激光器的电噪声特性，包括电噪声的种类、特点、产生机制、主要应用等。然后介绍了半导体激光器噪声常用的测量方法，以直接测量法为基础，结合互谱技术建立起半导体激光器噪声测试系统。在此基础上，开展了噪声用于半导体激光器质量表征和可靠性筛选等方面的研究工作。具体包括以下几个方面：对封装好的30余只808nm GaAs/GaAlAs高功率量子阱半导体激光器进行了电导数、低频电噪声测量和电老化测试。实验表明，器件在<WP=68>小电流注入下的电噪声反映了器件内部的缺陷,这与器件的质量和可靠性密切相关。在电老化过程中逐渐增加老化电流，对每次老化后的噪声进行测试，通过对比测试结果，确定出了器件噪声由下降到上升的转折点，即确定出器件在老化时所加电流偏置的最大值。通过这个最大值限定老化时的偏置电流,可以避免器件在老化过程中引入新的缺陷，使器件的质量和可靠性免受影响。同时，在加速老化的条件下研究了1/f噪声，产生－复合噪声（g-r噪声）和爆破噪声。实验发现g-r噪声、爆破噪声与电老化时所加偏置电流的大小有关，预示着g-r噪声和爆破噪声可能是器件退化的明显标志。将小波变换引入对半导体激光器的噪声分析和可靠性评价中。小波变换能同时在时域和频域中对信号进行分析，可以有效地区分信号的突变部分和噪声，因此利用小波变换，可以提取半导体激光器的噪声信号的1/f成分，而正是1/f噪声反映了材料或器件的不完整性，它是与器件质量密切相关。利用小波变换的时频局部化特性，将电噪声测试中得到的时域曲线进行多尺度分析，从而能够有效的分析器件的瞬时变化，评估器件的好坏，为器件的可靠性评价提供了新的途径。测试了广泛应用于节能灯电源及彩色电视机高频视放电路的三种双极晶体管2688B，2688S，2688，这三种晶体管均为NPN型。在研制和生产这些晶体管过程中，采用了三种不同的终端技术。对这三种样品进行电噪声测试，通过对比它们的电噪声大小与CB结漏电流的相互关系，发现漏电流大的样品其电噪声也大。研究结果表明了采用覆盖结构的终端技术可以有效地控制晶体管的表面漏电流，降低晶体管的电噪声，提高晶体管的可靠性。这一结果对同类产品的研制、生产具有参考价值。以直接测量方法为主，结合互谱技术，建立了半导体激光器噪声测试系统。采用双重屏蔽技术，即内屏蔽采用浮地方式消除地流环，外屏蔽采用多点接地以消除电磁场的干扰，有效地抑制了外界干扰对测量结果的影响。该测试系统的本底噪声小于1nv/Hz1/2，采用互谱技术后可达到0.1nv/Hz1/2。系统采用大容量电瓶为激光器提供驱动电流，采用适当的滤波和分压技术，使驱动电路可以提供10μA-600mA宽范围的驱<WP=69>动电流，有效地减少了驱动电流涨落对测试结果的影响，取得了满意的效果。更多还原

【Abstract】 With the development of the high and new technology re, semiconductor lasers (LDs) as a kind of important light source are widely used in optical fiber communication, optical sensor, information memory, medical treatment, pumping solid lasers and optical fiber amplification . The quality and reliability of semiconductor lasers is imperative in all the applications. The study on the reliability of LDs and its regularity is very significant to improve their specific property and use them rightly. At present, the usual method of screen is electric aging by increasing the temperature and aging current to measure LDs threshold, quantum efficiency and output power. These devices with high variance of output optic power at some current or high variance of the drive current at some output power will be screened, and the reliability of the devices will be classified according to the value of variance. The result of aging is statistic, and the time is long. During the aging, the lifetime of the reliable devices is also affected because of the hot and electric impulsion. It can cause batches of devices damage when some accidence happens, such as the uncontrolled system or power cut. On the other hand, electric aging is not sensitive for potential defects, for example, some devices after electric aging screening which are reliable are usually found fail rapidly during using. Thus, it is significant to find a kind of a fast, nondestructive, convenient method to test the devices and estimate their reliability.When the semiconductor laser is operating in a constant bias current, the terminal voltage of the device often fluctuates. The fluctuation that is named electric noise indicates the imperfects of material or device, especially; it is very sensitive for various reliability-dependent defects than other parameters. The noise test may estimate the quality and the reliability of the single device. Moreover, the voltage and current added on the device is near or under the normal stress level of the device, so that it is nondestructive to the device. So the electric noise is becoming a useful <WP=71>tool to characterize device quality and reliability. Thus, it is very significant for the preparing, manufacturing, using the devices to apply the fast, sensitive, nondestructive method to the test the devices and estimate their reliability.First, the electric noise characteristic of semiconductor lasers is reviewed, including the kind, character, produce mechanism, ect. Secondly, the measuring methods of noise in semiconductor lasers are introduced. Based on direct measuring and cross-spectrum measuring methods, we construct the measuring system of noise in semiconductor lasers. Next, the work on noise used to characterize quality and reliability of semiconductor lasers is first studied. The main research contents of this paper are shown hereinafter:1. The devices used in the experiment are 808nm GaAs/GaAlAs semiconductor laser diodes. Their epitaxial layer are grown by MOCVD technique. The electric derivative and the low frequency electric noise of devices are measured and the aging test is made. The results indicate the noise at the low injecting current reflects the inner defects of the device, which is related with the quality and reliability of the device. The aging current is increased gradually during aging and the noise is measured after aging at a time. By contrasting the results, we find the turning point of the noise value from the descending to the ascending, namely the maximum of the bias current added on the device when aging. Using the maximum may avoid inducing the new defects which effect on the quality and reliability of the device during aging. At the same time, 1/f noise, g-r noise and burst noise are studied under the condition of the accelerating aging. The results indict that g-r noise and burst noise is related with the value of the bias current added on the device when aging, and foretell that g-r noise and burst noise are possibly the evident symbol of the device degeneration.2. Wavelet is used to ana更多还原