通信工程文献翻译——摘要：硅太阳电池中过剩载流子衰减的度量对检测材料质量具有重要意义。本文研究了太阳能硅中过量载流子在激光脉冲激励后随时间的衰减。对于这种展现不同缺点的高密度材料，可以采取一种简化的方法来解决过量载流子扩散方程。我们使用适当的少数载流子寿命模型，用数字来计算过量载流子的时间衰减。通过测量使用发射微波表面钝化后的太阳能硅晶圆得到数据，随后，将这些计算数据与实验资料相比较。一个很好的一致性理论和实验结果给出了进一步评价通过使用载流子衰减时间的间质铁和少数载流子困住的基础。

1引言

由于光伏市场的迅速增长，目前太阳能硅片的生产数量超过了半导体工业硅片。两种材料之间的差异产生于各行业的不同要求。生产微电子芯片需要极其纯的硅，过去生产太阳能电池的硅是很廉价的，但对于高效率的太阳能电池来说仍然足够纯。通过降低质量标准和简化生产流程达到了降低生产成本的目的。这导致硅中含有大量的不同缺陷和杂质。这种类型的硅称为太阳能硅片。由于太阳能电池具有较强的耐用性，所以太阳能硅的质量可以低于用于生产微电子设备的硅。为了说明太阳能硅可以生产高效率太阳能电池，适当的表征手段是非常必要的。

微波检测光电导衰减（MWPCD）系统是一种广泛使用的硅质量检测工具。此工具使用被微电波反射过程中发现的硅中反射率的改变，测定了激光脉冲激发后的过量载流子衰减时间。这些数据揭示了一个同揭示少数载流子寿命等同的时间常数，对于薄的和表面钝化的太阳能硅片，这种先进的评估方法可应用于MWPCD系统，这使得提取少数载流子寿命作为过量载流子密度函数。为了加深对该种算法的理解，本文着重论述了过多的载流子衰减与各自的数值模拟之间的比较。为了达到这一目的,我们简化过量载流子的扩散方程，在衰减过程中，假设一个空间均匀的过量载流子轮廓。剩下的微分方程数值求解，考虑不同Shockley-Read-Hall重组过程和螺旋钻重组。计算的结果都是......

abstract

An understanding of the measured excess carrier decay in solar silicon is needed for a meaningful characterization of the material quality by this method. This paper studies the time decay of excess carriers

after laser pulse excitation in solar silicon. For this material, which exhibits a high density of different defects, a simplified approach to solve the diffusion equation of the excess carriers can be taken. We calculate the time decay of the excess carriers numerically by using an appropriate model of the bulk minority carrier lifetime. These calculations are subsequently compared to experimental data, which are obtained by measuring the photoconductance decay using reflected microwaves in surface passivated solar silicon wafers. A very good agreement between theoretical and experimental results gives the base for further evaluation of interstitial iron and minority carrier traps using the excess carrier decay.

1. Introduction

At present the volume of solar silicon production exceeds the production of silicon for the semiconductor industry, since the photovoltaic market is rapidly growing. The differences between both types of material arise from the differing requirements in the respective industry sector. An extremely pure silicon is needed to fabricate microelectronic chips, whereas silicon used to produce

solar cells has to be cheap, but still sufficiently pure for solar cells with high efficiency. The cost reduction is reached by decreasing the quality standards and by introducing simplified roduction

processes. This leads to silicon, which contains a large amount of different defects and impurities. This type of silicon is referred to as solar silicon. Due to the robustness of the solar cell process, the solar silicon quality can be lower than the quality of silicon used in microelectronics. To clarify the question, which quality of solar silicon can produce efficient solar cells, appropriate characterization methods are needed.

A widely used tool to characterize the quality of silicon is the microwave detected photoconductance decay (MWPCD) system.

This tool determines the time decay of the excess carriers after laser pulse excitation using the change in the reflectivity of the......