Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

Savtchouk

2015

MSF

In this work we propose a novel approach to measuring doping concentration in SiC based on a micro-scale time-resolved corona-Kelvin technique. In this method corona charging of SiC surface into depletion is done within a micro size corona spot and a Kelvin-force micro-probe is used to measure surface voltage decay in the center of the spot. The voltage decay is due to charge decay due to surface diffusion producing analogy of voltage-charge scanning under the probe. We use 2D charge diffusion analysis to extract two parameters – 1) doping concentration in the SiC epitaxial layer and 2) diffusion coefficient of corona ions on the SiC surface. The micro-spot corona-Kelvin method demonstrated in this work shall prove of importance for testing of doping uniformity on micro scale and measurements on a small area in SiC production wafers.

Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

A Novel Approach to Measuring Doping in SiC by Micro Spot Corona-Kelvin Method

Savtchouk

2015

MSF

“…In the macro-configuration a 1-mm diameter Kelvin probe is used, while corona charge is deposited on the area of 5mm diameter (2). In microconfiguration a 10µm diameter Kelvin force probe is employed, while the corona charge area is controlled to below 100 µm diameter using a 500 µm diameter aperture and an electrostatic bias of the same polarity as the corona charge (5,6).…”

Section: Corona -Kelvin Methodsmentioning

confidence: 99%

Model-Based Corona Charge - Kelvin Probe Characterization of Patterned Structures

Łagowski

2018

ECS Trans.

A model based analysis of corona charge -Kelvin probe measurement enables extension of this powerful non-contact electrical characterization metrology to patterned structures with multiple distinctly different elements within the probing area under the Kelvin probe. The model considers the geometrical dimensions, the electrical parameters of the elements of the patterned structure, and the response of each element to corona charging. Application of the model was verified on two types of patterned structures: a planar configuration with elements consisting of metal-oxidesemiconductor and oxide-semiconductor areas; and a three dimensional configuration with elements of trenches filled with metal and oxide-semiconductor. The model based QV method enables extraction of electrical parameters that are representative of the individual elements of the structure.

“…A miniaturization of both the Kelvin probe and corona deposition area has extended the corona-Kelvin metrology to small spot measurements on product silicon IC wafers and specifically to scribe line test sites, which are 100 m  100 m or smaller [11,12]. This transition to micro scale was achieved due to two developments: 1. refinement of the Kelvin force micro-probe technique enabling surface voltage measurement in a 10m diameter area and without sacrificing speed and precision in comparison to the large 2mm diameter Kelvin probe; 2. miniaturization of the corona discharge gun to achieve precise charging within a diameter down to 40 m.…”

Section: Introductionmentioning

confidence: 99%

“…Taking advantage of this phenomenon, we have developed the kinetic approach to electrical micro-characterization, which is based on time resolved monitoring of the surface voltage in the center of the charging spot and a procedure for the transient analysis that includes rigorous mathematical treatment of two dimensional surface diffusion. This methodology was applied to quantify the dielectric capacitance and the surface diffusion coefficient of corona ions [11,12].…”

Section: Introductionmentioning

confidence: 99%

A Method for Effective Work Function Monitoring

Loy²,

Edelman

et al. 2016

ECS Trans.

Monitoring of the effective work function (EWF) is proposed that involves quantification of the flatband voltage early during metal gate fabrication process by a non-contact micro corona-Kelvin, enabling faster feedback than traditional MOS capacitor based measurements. Two key elements are: 1. corona charging and 2. Kelvin probe force microscopy, KPFM. The surface voltage decay after corona charging is measured with KPFM under modulated light enabling parameter free extraction of the flatband voltage, VFB and EWF. Results for n- and p-type metals show excellent correlation with end of line CV measurements. The micro corona-Kelvin method allows quantification of two more EWF sensitive parameters: silicon surface potential barrier and the tunneling barrier at the metal / high-k dielectric interface. Results for n- and p-type metals are consistent with the expected behavior.