A DLTS Study of SiO2 and SiO2/SiNx Surface Passivation of Silicon

Abstract

Deep Level Transient Spectroscopy (DLTS) has been applied to Metal-Oxide-Semiconductor (MOS) capacitors fabricated on crystalline silicon n-and p-type substrates, with a SiO 2 or a SiO 2 /SiN x passivation stack, covered by an Al gate. It is shown that similar interface state distributions are obtained in both cases, from which it is concluded that the SiN x deposition does not degrade the interface. It is also shown that a rather large density of dangling bond defects is present at the Si/SiO 2 interface, which is related to the absence of a post metallization forming gas annealing.

Deep Level Assessment of n-Type Si/SiO2Metal-Oxide-Semiconductor Capacitors with Embedded Ge Quantum Dots

“…As the samples have not been passivated by a FGA, the most likely candidates for the observed electron trap(s) are the silicon dangling bond acceptors (P b 0/− ) in the upper half of the bandgap. 38,39,[45][46][47][48][49] Oxide traps in the lower quality 50 nm deposited SiO 2 correspond with rather large tunneling times, if they are deeper than 5 nm from the interface, practically excluding this explanation.…”

“…[37][38][39] For a bias pulse in depletion, mainly deep levels in the silicon depletion region, with a possible contribution from interface states, are probed. Pulsing to V FB or beyond (more positive bias) emphasizes the contribution of the interface states in the upper half of the bandgap and possibly also populates so-called border traps in the SiO 2 .…”

“…One possibility is that the presence of an increasing amount of Ge with QD size at the Si/SiO 2 interface creates different types of dangling bond centers, whereby one or more Ge atoms replace the silicon back-bond atoms in the P b centers. 50 The density of interface states (D it ) can be derived from the DLTS amplitude according to: 14,38,44 …”

Recent Developments on Silicon Based Solar Cell Technologies and their Industrial Applications

“…The double stack antireflection coating is also stable against external stress, which is beneficial for the fabrication of solar module. [42] Bi-layer schemes with different dielectric materials, like SiO 2 capped with SiN x , have also been explored [43].…”

Characterization of Al/Si junctions on Si(100) wafers with chemical vapor deposition-based sulfur passivation

“…Among the many techniques for surface passivation on Si, thermal oxidation of Si provides arguably the best-quality passivation [1][2][3]. Si nitride (SiN x ) by plasma-enhanced chemical vapor deposition is widely used in Si photovoltaic solar cells for both surface passivation and antireflection [4,5].…”