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，以实现这些器件的欧姆接触。需要开发具有低接触电阻的材料，但是，尚未建立设计和开发宽禁带半导体接触材料的指南。这项研究主要有两个目的：（i）了解电学之间的相关性。接触/半导体界面的（接触）特性和界面微观结构，以及（ii）扫描隧道显微镜/电位计（STM/STP）电势测量。首先，通过沉积金属层制备SiC和GaN的接触材料，然后对于 SiC 接触，在接触/SiC 界面处形成反应和产物，即 Ti_3SiC_2 化合物……从微观结构分析的结果来看，TiAl基接触在欧姆接触的形成中发挥着重要作用，另一方面，MOCVD-GaN衬底中形成的穿透位错的密度为。发现对接触中的接触形成或电流传输有很大影响，为了制造宽带隙半导体的高性能欧姆接触，了解和控制微观结构非常重要。通过 STM/STP 技术测量接触/半导体界面附近的电压降。优化了 STP 测量的样品制备程序，尽管测量在技术上并不简单，但在界面处检测到了轻微的电位变化。，该技术被认为主要用于识别接触/半导体界面处的电流传输路径。