Murad, SNA;Baine, PT;McNeill, DW;Mitchell, SJN;Armstrong, BM;Modreanu, M;Hughes, G;Chellappan, RK

2012

December

Solid-State Electronics

Optimisation and scaling of interfacial GeO2 layers for high-kappa gate stacks on germanium and extraction of dielectric constant of GeO2

Published

28 ()

ELECTRICAL-PROPERTIES SURFACE PASSIVATION CHANNEL MOSFETS MOS CAPACITORS DEVICES FILMS

78

136

140

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-kappa gate stacks on germanium. Thermally grown GeO2 layers have been prepared at 550 degrees C to minimise GeO volatilisation. GeO2 growth has been performed in both pure O-2 ambient and O-2 diluted with N-2. GeO2 thickness has been scaled down to approximately 3 nm. MOS capacitors have been fabricated using different GeO2 thicknesses with a standard high-kappa dielectric on top. Electrical properties and thermal stability have been tested up to at least 350 degrees C. The K value of GeO2 was experimentally determined to be 4.5. Interface state densities (D-it) of less than 10(12) CM-2 eV(-1) have been extracted for all devices using the conductance method. (C) 2012 Elsevier Ltd. All rights reserved.

OXFORD

0038-1101

10.1016/j.sse.2012.05.048