雜質半導體顧名思義是在半導體中參雜雜質，在半導體製程過程中參入微量的原子能夠使材料的物理性質改變，而雜質又分為施子(donor)與受子(acceptor)，分別形成以自由電子為多數載子的N型半導體，和以電洞為多數載子的P型半導體。定性及定量的量測微量雜質的參雜濃度是半導體製程中不可或缺的程序。而在參雜濃度低到一定程度時，許多的量測工具不再準確，例如：XRD。在這個研究中，我們使用二次諧波作為量測參雜硼之超薄矽薄膜的工具，在實驗中發現二次諧波對於參雜的物種以及濃度非常敏感，能夠隨著二次諧波的變化明顯觀察到不同參雜濃度產生的不同電場變化趨勢。隨後，我們研究P型超薄薄膜表面與氧氣吸附的關係，能夠看到氧氣吸附於材料表面後，二次諧波訊號的明顯變化。最後，由於此研究的材料具有P-N接面，因此我們也對於P-N接面去做檢測，證明P-N接面不影響此研究之數據趨勢。

Impurity semiconductors, as the name implies, are doping something mixed in semiconductors. In the process of semiconductor manufacturing, the addition of a small amount of atoms can change the physical properties of the materials. However, the doping atoms are divided into donors and acceptors, which are formed to N-type semiconductors with electrons as majority carriers, and P-type semiconductors with holes as majority carriers.
Qualitative and quantitative measurement of doping concentration of microscale atoms is an indispensable procedure in semiconductor manufacturing. However, when the doping concentration is low to a certain level, many measurement tools are no longer accurate, such as XRD. In this study, we used second harmonic generation (SHG) as a tool to measure boron-doped silicon ultrathin film. It was found in the experiment that the second harmonic is very sensitive to the species and concentration of the doping, then we can obviously observed different trends of electric field generated by different doping concentrations. Subsequently, we studied the relationship between the surface of the P-type ultra-thin film and the oxygen adsorption, and we can see the obvious change of the SHG signal after the oxygen is adsorbed on the surface of the material. Finally, since the material in this study has a P-N junction, we also test the P-N junction to prove that the P-N junction does not affect the data trend of this study.

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