OPTICAL AND ACOUSTICAL PROPERTIES OF INTERFACE IN DIRECT BONDING SEMICONDUCTORS

近年来，各种直接键合硅的制备技术已经建立起来，并有望在实际器件中得到应用。明确了键合机理，发现键合强度达到硅块体的断裂强度。另一方面，金属与半导体之间的接触问题对于基础研究和器件应用仍然具有重要意义采用微波和电阻测量的方法研究了直接键合硅中光激发载流子的动力学特性。材料中载流子的扩散系数为30,000cm/s^2。尽管该材料的扩散系数很大，但在4.2K时，一方晶片表面产生的电子无法到达另一方晶片。在直流测量中，一个晶圆的电阻率的温度依赖性受到另一个晶圆表面的光激发的影响本文报道了Ti/Si金属半导体系统在平行和垂直于界面方向上的输运性质。详细分析了电阻率测量中的分流效应引起的异常。发现上述异常与肖特基势垒高度密切相关。出现分流效应明显迹象的临界温度约为250K.[3]通过远红外磁光吸收和光学检测回旋共振测量，明确了外延生长ZnSe、GaAs和InGaAs中晶格失配和晶体缺陷的各种问题，以及CdTe中杂质的偏析问题。

Recently, various techniques to make direct bonding silicon are established and their application to actual devices are intended. The bonding mechanism is made clear and it was found that bonding strength reaches the fracture strength of silicon bulk. On the other hand, the contact problems between metal and semi-conductor are still important for basisc research as well as device application.[1] Dynamical properties of photoexcited carriers in direct bondong silicon are investigated by means of microwave and electrical resistance measurements.Diffusion coefficient of carriers in the material is found to be 30,000cm/s^2. In spite of large diffusion coefficient, electrons produced in a surface of one wafer of this material cannot reach the other wafer at 4.2K.In DC measurement, temperature dependence of resistivity of one wafer is influenced by photoexcitation on the othe face.[2] We report on an investigation of the transport properties of Ti/Si metalsemiconductor systems in the direction parallel and perpendicular to the interface. Anomalies caused by the shunting effect for resistivity measurements were analyzed in detail. It is found that the above-mentioned anomalies are closely related with the Schottky barrier height. The critical temperature at which a distinct indication of the shunting effect appears is around 250K.[3] Through the far-infrarerd magneto-optical absorption as well as the optically detected cyclotron resonance measurements, various problems for lattice-mismatch and crystal imperfection in epitaxially-grown ZnSe, GaAs and InGaAs and segregation problems of impurities in CdTe are made clear.