Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: SiC

HL 9.4: Vortrag

Montag, 22. März 2010, 12:15–12:30, H13

Apparently large ideality factors of MASS-diodes on the basis of the t-BN/SiC system — •Marc Brötzmann, Ulrich Vetter, and Hans Hofsäss — II. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany

A common feature of many heterojunction diodes is an anomalously large ideality factor above n=2 which has been observed in performed electrical characterizations. As the origin of such high ideality factors is not yet understood, we developed a quantitative model for the unusual diode characteristics on the basis of Metal - Amorphous Semiconductor - Semiconductor diodes (MASS-diodes) [1,2]. In this work, we investigate electrical properties of such diodes on the basis of heterostructure consisting of a crystalline semiconductor material, i.e. 6H-SiC, covered with a thin semiconducting film of amorphous or disordered material such as turbostratic boron-nitride (t-BN). These heterojunctions exhibit a pronounced rectifying behavior, low saturation current and low parasitic currents. Moreover, we observe an apparently giant ideality factor reaching values of n > 25. We demonstrate that the I-V characteristics of these MASS-heterojunctions are well described by a serial arrangement of an ideal Schottky-diode, a Frenkel-Poole type resistance and an Ohmic contact resistance, emulating a p-n- or Schottky diode characteristic with giant ideality factor.

[1] M. Brötzmann et al., JAP 106, 063704 (2009)

[2] M. Brötzmann et al., Proc. ICFSI 12 in PSS C, accepted (2009)