Title :
Optimisation and scaling of interfacial GeO2 layers for high-k gate stacks on germanium and extraction of dielectric constant of GeO2
Author :
Murad, S. N Ali ; McNeill, D.W. ; Mitchell, S.J.N. ; Armstrong, B.M. ; Modreanu, M. ; Hughes, G. ; Chellappan, R.K.
Author_Institution :
Sch. of Electron., Electr. Eng. & Comput. Sci., Queen´´s Univ. Belfast, Belfast, UK
Abstract :
Germanium is an attractive channel material for MOSFETs because of its higher mobility than silicon. In this paper, GeO2 has been investigated as an interfacial layer for high-k gate stacks. Thermally grown GeO2 layers have been prepared at 550 °C to minimize GeO volatilization. GeO2 growth has been performed in both pure O2 ambient and O2 diluted with N2. GeO2 thickness has been scaled down to 3.15 nm. MOS capacitors have been fabricated using different GeO2 thicknesses with a standard high-K dielectric on top. Electrical properties and thermal stability have been tested up to at least 350°C. The k value of GeO2 was calculated as 4.5. Interface state densities (Dit) of less than 1012 cm-2 eV1 have been extracted for all devices using the conductance method.
Keywords :
MOS capacitors; germanium compounds; high-k dielectric thin films; permittivity; semiconductor growth; thermal stability; GeO2; MOS capacitors; MOSFET; channel material; conductance method; dielectric constant extraction; electrical properties; high-k gate stacks; interface state densities; interfacial germanium oxide layer optimisation; interfacial germanium oxide layer scaling; standard high-K dielectric; temperature 350 degC; temperature 550 degC; thermal growth layer; thermal stability; Aluminum oxide; Dielectrics; Educational institutions; Logic gates; MOS capacitors; Materials; Thickness measurement;
Conference_Titel :
Semiconductor Device Research Symposium (ISDRS), 2011 International
Conference_Location :
College Park, MD
Print_ISBN :
978-1-4577-1755-0
DOI :
10.1109/ISDRS.2011.6135337
