\def \frameTitle {Prinzipien - Elon Musk}

\begin{frame}{\frameTitle}{}
   \begin{tikzpicture}
      \useasboundingbox (0,0) rectangle(\textwidth,0.8\textheight);
      \node [below right] at (current bounding box.north west){
         \begin{minipage}[t]{\linewidth}
         \end{minipage} 
      };
      \node[above right] at (current bounding box.south west) {
         \begin{minipage}[t]{\linewidth}
            \tiny
            \textbf{Quellen:}\\
         \end{minipage}
      };
   \end{tikzpicture}
\end{frame}