Study of Metal/Semiconductor Interfaces

我们已经研究了各种金属和宽间隙半导体、半导体、准GaN和四氢异碳薄膜之间的接口结构及其电子特性。这两部电影最近都有吸引力的、具有决定性的兴趣，作为新的功能电子和光子设备的有用材料。如何，金属接触到这些新材料通常会显示出不良特征，因为接触抵抗力很高，而且问题仍然存在，有待解决。我们在目前的研究项目中提出了一种新型的波长分散式x射线光谱仪，其中包括一个带有多容量x射线透镜的问题。一个多容量x射线透镜，一个从一个选定的0.1毫米直径样品区收集荧光x射线的装置。或者更少，更紧密地将它们放入一个接近平行光束的形式，并与传统的平板晶体结合在一起。自从我们用聚焦镜头把X射线束集中在兴奋的X射线束上，到现在的望远镜上大约10个微米。 ... More 使我们能够在空气中使用方便XRF的金属/半导体接口进行测试，以便在狭窄和局部区域进行测试。已经测试了几种金属作为欧姆接触物top-GaN的候选材料。在目前阶段，我们建议的是Pd/Nb/Au层结构的最佳金属。p-GaN中的不纯净性H是因为掺杂Mg而间接地降低激活效率到只有1%或甚至更低，所以在稳定和相对低抵抗力接触中有效地丧失和被电子金属结果捕获的。However，抵抗力在~ mΩ·cm 2的顺序下，对于实际应用来说还不够低。在添加到正确的电解金属选择，与镁结合使用氧或硅似乎有必要使接受者水平足够清晰，以实现客观、实用的低抵抗力接触。四氢离子碳（ta-C）对电子和结构性能的不同金属背面接触的影响已经研究了使用I-V测量、Raman和MeV离子散射光谱仪。各种金属类型，如Al、Au、Cr、Mo、Cu、W和Ti，已经使用了通过脉冲天主教电弧系统生长的后接触，以及电子测量和拉曼的反应显示，后接触影响了塔-C的发射特性，在与金属/ta-C界面形态和/或或通过MeV离子散射检测到的干扰，也清楚地显示了ta-C电影对界面属性产生影响的沉积条件。Less（低）

We have studied the interface structure and its electronic characteristics between various metals and wide-gap semiconductors, paricularly GaN and tetrahedral amorphous carbon films. Both of these films recently attract considerable interests as useful materials for new functional electronic and photonic devices. However, the metal contacts to these new materials usually show poor characteristics such as a very high contact resistivity, and the problem remains yet to be solved.Our conclusions and proposals in the present research project include ;1.We have presented a new type of wavelength dispersive x-ray spectrometer with a multi-capillary x-ray lens. A multi-capillary x-ray lens, a device that collects fluorescent x-rays from a selected sample area of 0.1 mm dia. or less and collimates them into a nearly parallel beam form, is combined with conventional flat crystals. Since we can focus the excitation x-ray beam down to about 10 micron meters using a focussing lens, the present spe … More ctrometer enables us to examine quite a narrow and local area such as the metal/semiconductor interfaces with the convenient XRF in air.2. Several metals have been tested as candidate materials for ohmic contacts top-GaN.At the present stage the best metal that we propose is the Pd/Nb/Au layered structure. The impurity H in p-GaN, which sticks the dopant Mg and consequently decreases the activation coefficient down to only 1 % or even less, is effectively deprived and trapped by the electrode metals resulting in a stable and relatively low-resistivity contact. However, the resistivity is in the order of〜mΩ・cm2, not low enough for practical applications. In addition to the proper choice of electrode metals, co-doping ofimpurity oxygen or silicon together with Mg seems to be necessary to make the acceptor levels sufficiently shallower for eventualy practical low-resistivity contacts.3. The effect of different metal back contacts on the electrical and structural properties of the tetrahedral amorphous carbon (ta-C) has been studied using I-V measurements, Raman and MeV ion scattering spectrometries. Various metal such as Al, Au, Cr, Mo, Cu, W, and Ti have been used as back contacts of ta-C grown by a pulsed cathodic arc system, The electrical measurements and Raman response showed that the back contact does influence the emission properties of ta-C, in a good agreement with the metal/ta-C interface morphologies and/or inter diffusions detected by MeV ion scattering.Also clearly shown is that the deposition condition of ta-C films affects the interface properties. Less