Relaxed SiGe Films by Surfactant Mediation

Tech ID: 10181 / UC Case 2000-304-0


Relaxed SiGe has become an important material in the fabrication of high-quality films for various applications. Strain-relaxed SiGe buffers have been produced by at least three known methods. However, these techniques present several disadvantages, such as long growth times, thick buffer layers, rough surfaces, high residual strain degree, and high threading dislocation densities. These problems can result in low yields, increased costs, and poor quality in the devices that are grown on the buffers. However, it has been found that a surfactant could be used to inhibit island formation in strain layer heteroepitaxy and, therefore, promote two-dimensional growth for the development of high-quality electron devices.


Scientists at the University of California have developed a novel method of using Sb as a surfactant to promote the growth of thin, high-quality relaxed SiGe buffers.

Suggested uses

This new technology has several uses in semiconductor production, including:

  • Ge or SiGe detectors grown on Si for 1.3 mm and 1.55 mm communications applications;
  • High Ge content Si1-XGeX/Si1-YGeY/Si1-ZGeZ heterojunction bipolar transistors (HBTs);
  • III-IV opto-electronic devices, such as light emitting diodes (LEDs) integrated on Si substrate using SiGe buffers graded to pure Ge.


The new UC technology provides the following benefits:

  • Produces thin buffers with low costs and high yields;
  • Low-temperature growth process can be integrated into any current type of processing technology that requires lower thermal budgets;
  • Greatly improves the quality of buffers in terms of both threading dislocation density and surface roughness.

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 6,995,076 02/07/2006 2000-304


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