一种新的确定少子产生特性的方法：———瞬态电容驰豫普方法

本文基于差值取样谱定理，指出一种用于同时确定少子寿命及表面产生速度的新方法－－－瞬态电容驰豫谱方法，该方法利用谱的峰值位置和高度能同时、准确、唯一地得到少子寿命及表面产生速度。同时将该方法与Ｚｅｒｂｓｔ方法得到的结果进行了对比。     

化学机械抛光产生的碲镉汞材料亚表面损伤层的研究

针对化学机械抛光工艺对碲镉汞材料所产生的亚表面损伤层进行了研究。利用椭圆偏振光谱方法对经过腐蚀剥层的碲镉汞材料表面进行了光学表征,认为化学机械抛光工艺造成的亚表面损伤层的深度大概为抛光工艺中所使用研磨颗粒直径的15~20倍。通过少子寿命表征和光导器件性能的对比测试,认为将该亚表面损伤层完全去除后,材料的少子寿命和器件的光电性能会得到明显的提高。     

脉冲MOS结构少子产生寿命的统一表征

本文提出了一种采用脉冲ＭＯＳ结构测量少子产生寿命的统一表征谱方法，此方法基于任何一种收敛弛豫过程均可以转换成一种衰减的指数函数的思想，应用关以样原理获得脉冲ＭＯＳ结构瞬态电容差值谱，从谱图中我们可以直接得到关于少子产生寿命信息。本文综合了众多脉冲ＭＯＳ结构测量少子产生寿命的物理模型，分析了不同模型之间的精细差别。     

半导体薄片少子寿命和表面复合速度的计算方法

用光电导衰退法测量半导体薄片的少子寿命时,由于表面复合的影响,通常从光照后少子衰退曲线中算得的表观寿命与实际的体寿命是相差很大的.本文给出了少子扩散方程的一种解法,计算表明,少子光电导衰退曲线用本方法解出的一次模和二次模的叠加来表示已是足够了.可以利用算得的一次模、二次模表达式从少子衰退曲线中算出表面复合速度和少子体寿命,其计算方法是比较方便的.本文还给出了一些实验和计算结果.     

用MOS恒定电荷法测定半导体少子的体产生寿命及表面产生速度

在MOS由深耗尽态恢复到平衡反型态的过程中,如果MOS系统的总电荷保持恒定,则用半导体表面势(ψ_s)与MOS的瞬态微分电压(dv/dt)之间的渐近线性关系,可以同时确定少子的体产生寿命及表面产生速度.实验装置可以直接显示ψ_s-dv/dt曲线,省去了Zerbst方法的繁琐作图程序.     

用CCWT方法确定少子的体产生寿命及表面产生速度

在MOS由非平衡深耗尽态恢复到平衡反型态的过程中,如果MOS系统的总电荷是恒定的,则空间电荷区宽度的瞬态特性W(t)将提供少子的体产生寿命τ及表面产生速度S的信息;用指数衰减函数比较法可以直接由W-t曲线确定τ、S,省去了Zerbst方法的繁琐作图程序.     

瞬态光响应法测试中波碲镉汞器件少子寿命的新方法

在测试中波碲镉汞光伏器件的瞬态响应时,当激光光斑照射器件表面位置距离光敏面较远时,器件表现为特殊的双峰脉冲响应现象,分析表明出现这种异常双脉冲现象的原因是光敏区内的少子漂移和光敏区外侧向收集的少子扩散有时间上的差异。通过对器件施加反向偏压,脉冲响应随反向偏压的增大由双峰变成单峰的实验结果,验证了少子侧向收集是导致器件形成双峰的主要原因。对第二个峰拟合得到p区的少数载流子寿命。将瞬态响应获得的少子寿命与该p型中波碲镉汞材料的理论计算和光电导衰退法得到的少子寿命相对比,发现三种方式得到的少子寿命随温度的变化趋势基本一致,这说明了可以通过瞬态光响应得到中波碲镉汞器件的少子寿命。     

有相异表面复合速度时半导体薄片少子连续方程的解及应用

本文给出了有相异表面复合速度时半导体薄片少子连续方程的一种新解法。数值计算结果表明,薄片的少子光电导衰退曲线可以用这种解的一次模和二次模之和来表示。可以使用这些结果讨论一些薄片的少子寿命和表面复合速度。     

适用于少子产生寿命CAM的线性电压扫描法

提出了 MOS电容线性电压扫描法测量半导体少子产生寿命的新方法。通过在 MOS C-t瞬态曲线上读取 n个不同时刻的电容值 ,确定出相应的少子产生寿命值。该方法基于最小二乘法原理 ,可有效地消除测量误差的影响 ,其精度随读取点的增加而提高 ,特别适合于少子产生寿命的计算机辅助测量。     

单晶硅表面金字塔大小及分布对少子寿命的影响

单晶硅表面钝化后少子寿命以及制成的太阳电池转换效率与单晶硅表面金字塔大小、形貌和分布密切相关。用不同的碱液刻蚀单晶硅表面,用SEM观察其表面绒面结构,测量了不同碱液刻蚀的单晶硅表面的少子寿命以及对应太阳电池的转换效率。实验研究表明,不同碱液刻蚀的单晶硅表面绒面结构形貌差异大,少子寿命明显不同。进一步研究发现,绒面上金字塔尺寸较大,且分布不均匀,则其少子寿命较短,对应太阳电池的转换效率较低;反之,绒面上金字塔小且分布均匀,则绒面少子寿命相对较长,对应的太阳电池转换效率相对较高。     

Graphical technique to determine minority carrier lifetime and surface generation velocity using triangular-voltage sweep C-V method

A simple graphical technique has been developed to determine minority carrier lifetime and surface generation velocity simultaneously. This technique is based upon the high frequency C-V characteristics derived in response to a triangular-voltage sweep. The simultaneous determination of both parameters with error less than 5% is possible as long as the two generation processes have a comparable rate. The bulk lifetime τ_B was measured over wide range of 10 nsec–10 msec, while surface generation velocity S can be measured over the range of 10^?3–10³ cm/sec. There is little influence of the parasitic capacitance, which greatly affects the Zerbst plot. This technique is suitable for process characterization due to its simplicity.     

Measurement of minority carrier lifetime and diffusion length in silicon epitaxial layers by means of the photocurrent technique

A new method for the determination of minority carrier lifetime and diffusion length in thin silicon epitaxial layers was developed. Using a transparent MIS structure the surface recombination velocity was reduced below 25 cm/s. This method makes possible to determine minority carrier lifetime and also diffusion length much greater than the thickness of the epitaxial layer.     

Separation of local bulk and surface recombination in crystalline silicon from luminescence reabsorption

Spontaneous photoemission of crystalline silicon provides information on excess charge carrier density and thereby on electronic properties such as charge carrier recombination lifetime and series resistance. This paper is dedicated to separating bulk recombination from surface recombination in silicon solar cells and wafers by exploiting reabsorption of spontaneously emitted photons. The approach is based on a comparison between luminescence images acquired with different optical short pass filters and a comprehensive mathematical model. An algorithm to separate both front and back surface recombination velocities and minority carrier diffusion length from photoluminescence (PL) images on silicon wafers is introduced. This algorithm can likewise be used to simultaneously determine back surface recombination velocity and minority carrier diffusion length in the base of a standard crystalline silicon solar cell from electroluminescence (EL) images. The proposed method is successfully tested experimentally. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of the minority carrier lifetime in crystalline silicon thin‐film material

The effective minority carrier lifetimes on epitaxial silicon thin‐film material have been measured successfully using two independent microwave‐detected photoconductivity decay setups. Both measurement setups are found to be equally suited to determine the minority carrier lifetime of crystalline silicon thin‐film (cSiTF) material. The different measurement conditions to which the sample under investigation is exposed are critically analyzed by both simulations and measurements on a large number of lifetime samples. No systematic deviation between the lifetime results from different measurement setups could be observed, underlining the accuracy of the determined lifetime value. Subsequently, a method to separate the epitaxial bulk lifetime and the total recombination velocity, consisting of front surface and interface recombination between the epitaxial layer and the substrate, is presented. The method, based on different thicknesses of the epitaxial layer, is applied to all batches of this investigation. Each batch consists of samples with the same material quality but different epitaxial layer thicknesses whereas different batches differ in their material quality. In addition, the same method is also successfully applied on individual cSiTF samples. From the results, it can be concluded that the limiting factor of the effective minority carrier lifetime for the investigated solar‐grade cSiTF material is the elevated recombination velocity at the interface between epitaxial layer and the substrate compared with microelectronic‐grade material. In contrast, the samples cannot be classified into different material qualities by their epitaxial bulk lifetimes. Even on multicrystalline substrate, solar‐grade material can exhibit high epitaxial bulk lifetimes comparable to microelectronic‐grade material. Copyright © 2012 John Wiley & Sons, Ltd.     

双面抛光单晶硅片少子扩散长度的测量

本文改进了常规表面光电压测试少子扩散长度法,采用环形下电极消除了薄样品背面光电压信号对测量结果的影响;应用阻尼最小二乘法数据处理原理对实验数据进行“曲线拟合”,求出少子扩散长度和背面表面复合速度。本文讨论了该方法的测量范围。     

Characterization of Generation Lifetime and Surface Generation Velocity of Semiconductor Wafers by a Contactless Zerbst Method

A contactless Zerbst method has been developed to characterize the generation lifetime and the surface generation velocity of a semiconductor wafer. This characterization is unaffected by the gate leakage current or the device fabrication process. In this study, this contactless Zerbst method was used to characterize the generation lifetime and the surface generation velocity of a partially Au-doped Si wafer. The results demonstrate that the contactless Zerbst method is a powerful technique for characterizing the generation lifetimes and the surface recombination velocities of semiconductor wafers.