为了成功构建半导体器件,半导体工业必须测量基本材料参数,特别是在开发新材料时;测量材料的生长质量;准确确定薄膜的细节,量子阱,和控制或影响器件性能的其他微结构;以及测量器件本身的性能。需要确定的属性,因此,包括基本能带结构和传输参数,例如能隙值和载流子散射时间;杂质和缺陷的存在和浓度;合金参数;层厚度;材料在复杂结构中的分布;和许多其他。这个过程确定了广泛的材料,结构,和设备参数称为表征。半导体行业使用许多表征方法,这些方法利用电气,化学,和其他方法。其中,光学表征技术,定义为使用紫外线到远红外线的电磁辐射,脱颖而出,因为他们电弧无损,需要最少的样品制备,因为没有接触电弧需要。这些特征对于生产使用或检查成品设备非常重要。另一个好处是,与需要固定触点的电气方法不同,光学技术可以给出半导体晶片范围内的属性的二维或三维图。本文描述的六种技术(旋光术,红外光谱,显微镜,调制光谱学,光致发光,和拉曼散射)之所以选择,是因为它们目前或可能在行业中广泛使用;它们测量广泛的半导体参数;并且它们在电磁频谱的不同区域中运行。对每种技术的讨论指出了测得的基本半导体量,给出了该技术的科学依据,并指出测量是如何进行的。详细讨论了文献中的说明性例子,显示重要半导体材料的应用。更多信息可以从所包括的参考文献的详细列表中获得。
To successfully construct semiconductor devices, the semiconductor industry must measure fundamental material parameters, especially when developing new materials; measure the quality of the material as it is grown; accurately determine the details of thin films, quantum wells, and other microstructures that control or affect device performance; and measure properties of the devices themselves. Properties that need to be determined, therefore, include basic band structure and transport parameters, such as energy gap values and carrier scattering times; the presence and concentration of impurities and defects; alloy parameters; layer thicknesses; the distribution of materials in complex structures; and many others. This process of determining a wide range of material, structural, and device parameters is called characterization. The semiconductor industry uses many characterization methods which draw on electrical, chemical, and other approaches. Among these, optical characterization techniques, defined as those using electromagnetic radiation from the ultraviolet to the far infrared, stand out because they arc nondestructive and require minimal sample preparation since no contacts arc needed. These features arc of great importance for production use or to examine finished devices. Another benefit is that, unlike electrical methods which require fixed contacts, optical techniques can give two- or three-dimensional maps of properties over the extent of a semiconductor wafer. The six techniques described in this paper (cllipsometry, infrared spectroscopy, microscopy, modulation spectroscopy, photolumincscence, and Raman scattering) were chosen because they are currently or potentially widely used in the industry; they measure a broad array of semiconductor parameters; and they operate in different regions of the electromagnetic spectrum. The discussion of each technique indicates the basic semiconductor quantities measured, gives the scientific basis of the technique, and indicates how the measurement is made. Illustrative examples from the literature are discussed in detail, showing applications to important semiconductor materials. More information can be obtained from the detailed list of references included.