Engineering High- k /SiGe Interface with ALD Oxide for Selective GeO x Reduction
- Univ. of California, San Diego, CA (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Stanford Univ., CA (United States)
- Univ. of Texas, Dallas, TX (United States)
Suppression of electronic defects induced by GeOx at the high-k gate oxide/SiGe interface is critical for implementation of high-mobility SiGe channels in complementary metal-oxide-semiconductor (CMOS) technology. Theoretical and experimental studies have shown that a low defect density interface can be formed with an SiOx-rich interlayer on SiGe. Experimental studies in the literature indicate a better interface formation with Al2O3 in contrast to HfO2 on SiGe; yet, the mechanism behind this is not well understood. In this study, the mechanism of forming a low defect density interface between Al2O3/SiGe is discovered using atomic layer deposited (ALD) Al2O3 insertion into or on top of ALD HfO2 gate oxides. To elucidate the mechanism, correlations are made between the defect density determined by impedance measurements and the chemical and physical structures of the interface determined by high-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. The compositional analysis reveals an SiOx rich interlayer for both Al2O3/SiGe and HfO2/SiGe interfaces with the insertion of Al2O3 into or on top of the HfO2 oxide. The data is consistent with the Al2O3 insertion inducing decomposition of the GeOx from the interface to form an electrically passive, SiOx rich interface on SiGe. This mechanism demonstrates that nanolaminate gate oxide chemistry cannot be interpreted as resulting from a simple layer-by-layer ideal ALD process, because the precursor or its reaction products can diffuse through the oxide during growth and react at the semiconductor interface. This finding shows that in scaled CMOS, remote oxide ALD (oxide ALD on top of the gate oxide) can be used to suppress electronic defects at gate oxide semiconductor interfaces by oxygen scavenging.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-05CH11231; ECCS-1542148
- OSTI ID:
- 1542398
- Journal Information:
- ACS Applied Materials and Interfaces, Vol. 11, Issue 16; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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