chap05.tex

% !TeX spellcheck = <en-US>
\chapter{Evaporations and measurement}
\section{Evaporation configuration}

To optimize the penumbra of Pb islands on a \ce{Si} sample, a series of evaporations were performed. The \ce{Si}(111) sample was prepared and cleaned according to the process described in Section \ref{sec:sample_prep}. The cleanliness of both the sample and mask was confirmed optically before they were inserted into the Load Lock.

Five evaporations were conducted to assess the edge sharpness of the evaporated dots at different distances. The measurements began at a distance of $25 \pm 5$ {\textmu}m from the sample. The approach curve to full contact was recorded, and the first evaporation was performed at this point of full contact. The approach curve is shown in Figure \ref{fig:evaporation_approach_curve}.

\begin{figure}[H]
    \centering
    \includegraphics[width=\linewidth]{img/Evaporation/Approach_Curve_Field01.pdf}
    \caption{The approach curve measured for field 1 until full contact.}
    \label{fig:evaporation_approach_curve}
\end{figure}

The 3 capacitance sensors appear heavily correlated and the uncertainty on C2 and C3 is an order of magnitude larger than the step in $dC$. For this reason C1 was primarily used for alignment. C2 and C3 were recorded but not utilized. The other evaporations were performed by retracting the mask $1000$ steps and approaching. 

The subsequent evaporations were performed by retracting the mask $1000$ steps and then approaching the sample. Four additional evaporations were conducted at different lateral positions on the sample. Each evaporation consisted of a $9 \times 9$ field of $3$ {\textmu}m Pb circles, as previously shown in Figure \ref{fig:mask_aligner_nomenclature_capacitances_mask}. Each field was evaporated at different mask-sample distances, as described by the approach curve. The evaporations were performed with the following stop conditions:

\begin{itemize}
	\item Field 1: $1$ {\textmu}m distance to sample (Full contact)
	\item Field 2: $16$ {\textmu}m distance to sample (First Contact)
	\item Field 3: $16$ {\textmu}m (Shortly before first contact at stop condition $0.12$ pF)
	\item Field 4: $4$ {\textmu}m (Second Contact)
	\item Field 5: $1$ {\textmu}m (Full Contact)
\end{itemize}

The parameters used for the evaporator are shown in Appendix \ref{app:evaporation}. The turbomolecular pump was by mistake not turned off during evaporation. \\

\begin{figure}[H]
    \centering
		\begin{subfigure}{0.45\linewidth}
		\centering
		\includegraphics[width=0.9\linewidth]{img/Evaporation/SampleImage.pdf}
		\caption{}
		\label{fig:Evaporation_diagramm_sample_img}
	\end{subfigure}
	\begin{subfigure}{0.45\linewidth}
		\centering
		\includegraphics[width=0.9\linewidth]{img/Evaporation/Mask01_Aspect.png}
		\caption{}
		\label{fig:Evaporation_diagramm_mask_img}
	\end{subfigure}
    
    \caption{(\subref{fig:Evaporation_diagramm_sample_img}) diagram showing the Evaporation performed on the sample. Red squares represent the positions of the evaporated fields. The number shows the order of evaporations. Distances are measured using an optical microscope. Fields are at a $10^\circ$ angle with respect to the sample holder. (\subref{fig:Evaporation_diagramm_mask_img}) microscope image of the mask taken before evaporation. The mask holder was aligned with respect to the camera view.}
    \label{fig:Evaporation_diagramm}
\end{figure}

After each evaporation the sample was moved laterally by $5000$ steps. Initially, the movement was in the -x direction, and after the third evaporation, the direction was reversed to +x. The final positions of the fields on the sample are shown in Figure \ref{fig:Evaporation_diagramm_sample_img}. \\
The fields were found to be angled at approximately 10° with respect to the sample edge. This misalignment is attributed to a slight deviation in the mask's positioning on the mask holder, as evident in Figure \ref{fig:Evaporation_diagramm_mask_img}.

\section{Contamination}
The entire surface of the sample is contaminated with small particles, approximately $50$ nm in height and $10$ nm in diameter. These contaminants are not visible under an optical microscope. Although the sample was cleaned, it was only inspected optically after cleaning, so it is unclear whether the contaminants were present after cleaning or were deposited later.

\begin{figure}[H]
    \centering
	\begin{subfigure}{0.495\linewidth}
		\centering
    	\includegraphics[width=0.95\linewidth]{img/Evaporation/Contamination.png}
		\caption{}
		\label{fig:evaporation_contamination_img}
	\end{subfigure}
	\begin{subfigure}{0.495\linewidth}
		\centering
    	\includegraphics[width=\linewidth]{img/Evaporation/Contamination.pdf}
		\caption{}
		\label{fig:evaporation_contamination_anal}
	\end{subfigure}
    \caption{(\subref{fig:evaporation_contamination_img}) AFM image of field $3$ without any grain removal applied. Data was obtained on multiple different spots on the sample. (\subref{fig:evaporation_contamination_anal}) line cuts obtained from contamination particles. \textcolor{tab_red}{Red} and \textcolor{tab_green}{green} lines show the average height and width of the contamination particles obtained from peak fits.}
    \label{fig:evaporation_contamination}