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Passivation of InP heterojunction bipolar transistors by strain controlled plasma assisted electron beam evaporated hafnium oxide

: Driad, R.; Sah, R.E.; Schmidt, R.; Kirste, L.


Applied Physics Letters 100 (2012), No.1, Art. 014102, 4 pp.
ISSN: 0003-6951 (Print)
ISSN: 1077-3118
ISSN: 1931-9401 (online)
Journal Article
Fraunhofer IAF ()

We present structural, stress, and electrical properties of plasma assisted e-beam evaporated hafnium dioxide (HfO 2) layers on n-type InP substrates. These layers have subsequently been used for surface passivation of InGaAs/InP heterostructure bipolar transistors either alone or in combination with plasma enhanced chemical vapor deposited SiO 2 layers. The use of stacked HfO 2/SiO 2 results in better interface quality with InGaAs/InP heterostructures, as illustrated by smaller leakage current and improved breakdown voltage. These improvements can be attributed to the reduced defect density and charge trapping at the dielectric-semiconductor interface. The deposition at room temperature makes these films suitable for sensitive devices.