Positive Charge in SOS Heterostructures with Interlayer Silicon Oxide

• Published in: Semiconductors (Woodbury, N.Y.) Vol. 52; no. 10; pp. 1341 - 1348
• Main Authors: Popov, V. P., Antonov, V. A., Vdovin, V. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-10-2018; Springer; Springer Nature B.V
• Subjects: ALUMINIUM OXIDES; Aluminum oxide; Bonding; Fabrication; HEAT TREATMENTS; Heterostructures; HOLE MOBILITY; Hydrogen; Interlayers; Magnetic Materials; Magnetism; MATERIALS SCIENCE; OXIDATION; Physics; Physics and Astronomy; Sapphire; SILICA; Silicon; Silicon dioxide; SILICON OXIDES; TEMPERATURE RANGE 0400-1000 K; Testing of Materials and Structures; THICKNESS; Treatment; Drain Gate Characteristics; Sapphire Layer; Thermal Silicon Dioxide Layer; Heterointerface; Intermediate Silicon-oxide Layer
• ISSN: 1063-7826; 1090-6479
• DOI: 10.1134/S1063782618100160

The continuous transfer of (001)Si layers 0.2–1.7 μm thick by implanted hydrogen to the
c
-sapphire surface during direct bonding at high temperatures of 300–500°C is demonstrated for the first time. The formation of an intermediate silicon-oxide layer SiO
x
during subsequent heat treatments at 800–1100°C, whose increase in thickness (up to 3 nm) correlates with an increase in the positive charge
Q
i
at the heterointerface to ~1.5 × 10
12
cm
–2
in contrast to the negative charge at the SiO
x
/Al
2
O
3
ALD heterointerface. During silicon-layer transfer to sapphire with a thermal silicon-dioxide layer,
Q
i
decreases by more than an order of magnitude to 5 × 10
10
cm
–2
with an increase in the SiO
2
thickness from 50 to 400 nm, while the electron and hole mobilities barely differ from the values in bulk silicon. Based on these results, a qualitative model of the formation of positively charged oxygen vacancies in a 5-nm sapphire layer near the bonding interface is proposed.