Electron spin resonance observation of an interfacial Ge P(b 1)-type defect in SiO(2)/(100)Si(1-x)Ge(x)/SiO(2)/Si...

Area of Science:

• Materials Science
• Semiconductor Physics
• Defect Characterization

Background:

• Germanium-Silicon (Ge(x)Si(1-x)) heterostructures are crucial in modern electronics.
• Understanding interface defects is vital for device performance and reliability.
• Previous research has focused on silicon-based defects, leaving Ge-related interface defects less understood.

Purpose of the Study:

• To identify and characterize novel germanium (Ge) dangling bond (DB)-type interface defects in SiO(2)/(100)Ge(x)Si(1-x)/SiO(2)/(100)Si heterostructures.
• To determine the properties and conditions under which these Ge DB defects form.
• To differentiate these defects from known silicon-based defects.

Main Methods:

• Electron Spin Resonance (ESR) spectroscopy was employed to detect and analyze interface defects.
• The study involved fabricating heterostructures using the condensation technique.
• ESR spectral analysis was performed, focusing on g-values and defect symmetry.

Main Results:

• The first Ge dangling bond (DB)-type interface defect, designated as a Ge P(b1)-type center, was observed.
• This defect exhibits monoclinic-I (C(2v)) symmetry with specific principal g values (g1=2.0338, g2=2.0386, g3=2.0054).
• Maximum defect densities of ~6.8 × 10^12 cm(-2) were found at Ge(x)Si(1-x)/SiO(2) interfaces with x ≈ 0.7, with signals absent outside the 0.45-0.93 range.

Conclusions:

• The observed defect is identified as a Ge P(b1)-type center, distinct from trigonal Ge P(b0)-type centers.
• The findings provide crucial insights into the role and behavior of Ge DB defects at Ge/insulator interfaces.
• This research expands the general understanding of interfacial dangling bond centers in semiconductor heterostructures.