HfO2 for strained-Si and strained-SiGe MOSFETs

• We report on HfO2 gate dielectrics grown by atomic layer deposition (ALD) at 600°C on strained-Si and strained-SiGe layers. The strain status in the Si layer remained unaltered after HfO2 deposition and an interface state density of ~1×1011 cm-2 eV-1 was obtained for the case of thick HfO2 films. The breakdown fields were in the range 2-5 MV/cm, which is high compared to HfO2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the case of a thin HfO2 film with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si0.77Ge0.23/Si. The carrier transport through these HfO2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltage

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

dielectric thin films

interface states

semiconductor materials

atomic layer deposition

elemental semiconductors

leakage currents

MOSFET

Ge-Si alloys

hafnium compounds

semiconductor device breakdown

silicon

Poole-Frenkel effect

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