BACKGROUND:  Relaxed SiGe is an important material for producing semiconductor devices, and current methods for producing relaxed SiGe buffers require long growth times, thick buffer layers, high residual strain, and high threading dislocation densities. These can result in low efficiency, high costs, and low yields. Also, devices manufactured from these methods are likely to perform poorly because of the reduced quality of the buffer layer and subsequently grown films.

INNOVATION:  Through the use of metallic surfactants, researchers at UCLA have demonstrated the growth of a high-quality, relaxed, and oriented SiGe buffer layer of relatively thin dimensions which can then be used for subsequent high-quality epitaxial film growth. This method provides enhanced buffer characteristics, such as low surface roughness and low threading dislocation densities.

POTENTIAL APPLICATIONS 

• High quality relaxed oriented SiGe buffers

ADVANTAGES

• Very low threading dislocation density
• Relatively thin buffers with a smooth surface

Reference: UCLA Case No. 2000-304

US Patent 6,995,076