Germanium MOS Capacitors with Hafnium Dioxide and Silicon Dioxide Dielectrics

Haydn Wadsworth, Sekhar Bhattacharya, David McNeill, Frederick Ruddell, Mervyn Armstrong, Harold Gamble, D. Denvir

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Germanium (Ge) does not grow a suitable oxide for MOS devices. The Ge/dielectric interface is of prime importance to the operation of photo-detectors and scaled MOSTs. Therefore there is a requirement for deposited or bonded dielectric materials. MOS capacitors have been formed on germanium substrates with three different dielectric materials. Firstly, a thermally grown and bonded silicon dioxide (SiO2) layer, secondly, SiO2 deposited by atmospheric pressure CVD ‘silox’, and thirdly a hafnium oxide (HfO2) high-k dielectric deposited by atomic layer deposition (ALD). Ge wafers used were p-type 1 0 0 2 O cm. C–V measurements have been made on all three types of capacitors to assess the interface quality. ALD HfO2 and silox both display acceptable C–V characteristics. Threshold voltage and maximum and minimum capacitance values closely match expected values found through calculation. However, the bonded SiO2 has non-ideal C–V characteristics, revealing the presence of a high density of interface states. A H2/N2 post metal anneal has a detrimental effect on C–V characteristics of HfO2 and silox dielectrics, causing a shift in the threshold voltage and rise in the minimum capacitance value. In the case of hafnium dioxide, capacitor properties can be improved by performing a plasma nitridation of the Ge surface prior to dielectric deposition.
LanguageEnglish
Pages685-689
Number of pages5
JournalMaterials Science in Semiconductor Processing
Volume9
Issue number4-5 SPEC. ISS.
DOIs
Publication statusPublished - Aug 2006

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Hafnium
Germanium
MOS capacitors
hafnium
dioxides
Silicon Dioxide
germanium
capacitors
Silica
silicon dioxide
Atomic layer deposition
Threshold voltage
atomic layer epitaxy
Capacitors
Capacitance
threshold voltage
Hafnium oxides
capacitance
MOS devices
Nitridation

Cite this

Wadsworth, Haydn ; Bhattacharya, Sekhar ; McNeill, David ; Ruddell, Frederick ; Armstrong, Mervyn ; Gamble, Harold ; Denvir, D. / Germanium MOS Capacitors with Hafnium Dioxide and Silicon Dioxide Dielectrics. In: Materials Science in Semiconductor Processing. 2006 ; Vol. 9, No. 4-5 SPEC. ISS. pp. 685-689.
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Germanium MOS Capacitors with Hafnium Dioxide and Silicon Dioxide Dielectrics. / Wadsworth, Haydn; Bhattacharya, Sekhar; McNeill, David; Ruddell, Frederick; Armstrong, Mervyn; Gamble, Harold; Denvir, D.

In: Materials Science in Semiconductor Processing, Vol. 9, No. 4-5 SPEC. ISS., 08.2006, p. 685-689.

Research output: Contribution to journalArticle

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