(Invited) Second Harmonic Generation: A Powerful Non-Destructive Characterization Technique for Dielectric-on-Semiconductor Interfaces

Abstract

The second harmonic generation (SHG) proved to be a very promising characterization technique for dielectric-semiconductor interfaces because it is sensitive, non-destructive, can be applied directly on wafer, at different stages of wafer processing. The method, based on non-linear optics effects, is measuring a signal encompassing the "static" electric field at the dielectricsemiconductor interface which is directly related to the oxide charges Q ox and to the interface state density D it. A general methodology for Q ox and D it extraction from SHG measurements requires (i) calibration based on parameters obtained by classical electrical methods and (ii) modeling to capture the optical propagation phenomena that impact the SHG signal. In this paper, we discuss these issues based on a review of our recent advances on how to exploit SHG for dielectrics on semiconductor characterization.

Quantifying the Impact of Al Deposition Method on Underlying Al2O3/Si Interface Quality

“…Finally, the investigated influence of different metal deposition methods and the different annealing steps on the oxide–semiconductor interface show that the COCOS characterization possesses several benefits in comparison to using the second harmonic generation (SHG) method [ 48 ] or the traditional investigation by measuring C–V curves of MOS capacitors. First, there is no requirement to precisely know the sample geometry (SHG and MOS).…”

Characterization of interface charge traps in PE-TEOS and HDP oxide with different annealing temperatures using time-dependent second-harmonic generation

“…in the oxide layer. The reflected TD-SHG intensity from the Si/SiO2 interface is described as [8,9]: (2) + 𝜒 (3)…”

“…where 𝜒 (2) and 𝜒 (3) are the effective nonlinear second-and third-order susceptibilities near the interface, respectively. The quasi-static electric field, EDC (t), is related to the interface trap density.…”

“…One of the unique features of SHG measurements is that they are sensitive to the interfacial electric field generated by fixed oxide charge (Qox) and interface traps density (Dit). Recently, SHG has been used to investigate oxide charge and interface state densities in alumina (Al2O3) on p-type silicon [3], and similar structures have been investigated for CMOS image sensor applications [4]. While the characterization of different dielectric interfaces on silicon based on SHG has been developed [3][4][5], little attention has been paid to oxide charge traps in SiO2/Si interfaces generated by different deposition techniques, such as PE-TEOS and HDP chemical vapor deposition (CVD) processes, even though the interface properties are strongly influenced by the deposition source [6,7].…”