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Ohmic contact materials for wide-gap semiconductors : Fabrication and STP analysis.

宽禁带半导体的欧姆接触材料：制造和 STP 分析。

基本信息

批准号：
15206069
负责人：
MURAKAMI Masanori
金额：
$ 26.79万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Wide-band-gap compound semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) have excellent intrinsic properties, and thus are suitable for application to next-generation communication and power electronic devices. In order to realize these devices, ohmic contact materials with low contact resistances are required to develop. However, a guideline of designing and developing the contact materials for the wide-gap semiconductors is not established. This study are focused on two fold purpose : (i)understanding of correlation between electrical (contact) properties and interfacial microstructures of the contact/semiconductor interfaces, and (ii)scanning tunneling microscopy/potentiometry (STM/STP) measurements of electrical potentials.First, the contact materials for SiC and GaN were prepared by depositing metal layers and subsequently annealing in a vacuum. As for the contacts for SiC, the reaction and products formed at the contact/SiC interfaces, i.e.Ti_3SiC_2 compounds … More for TiAl-based contacts, was found to play an important role in formation of the ohmic contacts from the results of microstructural analysis. On the other hand, the density of the threading dislocations, which were formed in the MOCVD-GaN substrates, was found to have strong influences on the contact formation or current transport in the contacts. Consequently, understanding and control of the microstructures were very important in order to fabricate high performance ohmic contacts for the wide-gap semiconductors. In addition, the potential distribution (voltage drop) near the contact/semiconductor interfaces was measured by the STM/STP technique. The procedures of the sample preparation for the STP measurements were optimized, and the potential changes were detected slightly at the interface. Although the measurements are not technically straightforward, this technique was believed to apply extensively in order to identify the paths of the current transport at the contact/semiconductor interfaces. Less

碳化硅（SiC）和氮化镓（GaN）等宽带隙化合物半导体具有优异的本征特性，因此适合应用于下一代通信和电力电子器件。为了实现这些器件，需要开发具有低接触电阻的欧姆接触材料。然而，宽禁带半导体接触材料的设计和开发还没有一个指导方针。本论文的主要目的有两个：（i）了解接触/半导体界面的电学性质与界面微结构之间的关系，（ii）利用扫描隧道显微镜/电位法（STM/STP）测量接触电位。首先，通过沉积金属层并在真空中退火制备SiC和GaN的接触材料。对于SiC的接触，研究了在接触/SiC界面处的反应和生成物Ti_3SiC_2化合物 ...更多信息对于TiAl基接触，从微观结构分析的结果发现，在形成的欧姆接触中起着重要的作用。另一方面，发现在MOCVD-GaN衬底中形成的穿透位错的密度对接触形成或接触中的电流输运具有强烈的影响。因此，了解和控制的微结构是非常重要的，以制造高性能的宽禁带半导体欧姆接触。此外，通过STM/STP技术测量接触/半导体界面附近的电位分布（电压降）。优化了STP测量的样品制备程序，并在界面处检测到轻微的电位变化。虽然测量在技术上并不简单，但这种技术被认为可以广泛应用，以确定接触/半导体界面处的电流传输路径。少