4H-SiC界面飞秒激光退火及其电学性能优化

Femtosecond laser annealing of 4H-SiC interfaces and optimization of their electrical performance

改善SiC与金属界面间的电接触性质有助于推动SiC材料在高频高功率器件领域的发展。采用波长为1030 nm近红外飞秒激光退火处理4H-SiC表面,研究了不同激光参数对退火效果的影响。通过扫描电镜、X射线光电子能谱仪、共聚焦拉曼光谱仪等分析表征手段,探究了飞秒激光退火样品的表面形貌、元素分布及成键结构的变化。研究发现,接触界面电学性能的变化来自于激光退火产生的无序石墨结构以及具有O空位缺陷的SiOx/Si结构,这种结构不仅降低了界面肖特基势垒高度,提升了界面电导率,而且改变了4H-SiC表面的费米能级,从而大幅提升了界面电学性能。通过飞秒激光退火,实现了SiC界面肖特基势垒从1.43 eV到0.69 eV的变化,载流子浓度从5.40×10^(13)cm^(-3)变化为1.77×10^(18)cm^(-3)。本研究开发了一种利用超快激光退火优化SiC界面电学性能的有效方法。

Enhancing the electrical contact properties between SiC and metal interfaces is crucial for ad⁃vancing SiC materials in high-frequency and high-power devices.This study utilized a 1030 nm near-infra⁃red femtosecond laser to anneal the 4H-SiC surface,analyzing the effects of various laser annealing param⁃eters.We examined changes in surface morphology,element distribution,and bonding structure of the la⁃ser-annealed samples using scanning electron microscopy,X-ray photoelectron spectroscopy,confocal Ra⁃man spectroscopy,and other methods.The study revealed that improvements in electrical properties at the contact interface result from a disordered graphite structure and SiOx/Si structure with oxygen vacan⁃cies created by laser annealing.This structure reduces the interface Schottky barrier height,enhances con⁃ductivity,and shifts the Fermi level of the 4H-SiC surface,significantly boosting interface electrical prop⁃erties.Femtosecond laser annealing reduced the SiC interface Schottky barrier from 1.43 eV to 0.69 eV and increased the carrier concentration from 5.40×10^(13)cm^(-3)to 1.77×10^(18)cm^(-3),presenting a novel meth⁃od for optimizing SiC interface electrical properties with ultrafast laser annealing.