% based on Ch. 2 of "Systematic Design of Anlog Integrated Circuits: 
% Using Pre-Computed Lookup Tables" by Paul G.A. Jespers and Boris Murmann
\begin{axis}[ xlabel=$q$ %normalized mobile charge density
            , ylabel=$\mathrm{IC}\equal\nicefrac{I_{\mathrm{D}}}{I_{\mathrm{S}}}$ % normalized drain current
            , xmode=log
            , ymode=log
            , xmin=0.01
            , xmax=100
            , ymin=0.001
            , ymax=1000
            , grid=both
            , width= 12cm
            , extra x ticks={0.2,5}
            , extra x tick labels={0.2,5}
            ]

  \addplot[ mark=none
          , domain=0.01:60
          , samples=50
          , smooth
          , thick] {x^2+x}; 

  \addplot[ mark=none
          , domain=0.03:30
          , samples=50
          , smooth
          ] {x^2}; 

  \addplot[ mark=none
          , domain=0.01:100
          , samples=2
          , smooth
          ] {x}; 

  \draw[dashed] (axis cs:0.2,0.001) -- (axis cs:0.2,1000);
  \draw[dashed] (axis cs:5.0,0.001) -- (axis cs:5.0,1000);

  \draw[{Latex[round,scale=0.9]}-]
    (axis cs:0.3,0.09) -- (axis cs:0.4,0.02)
    node[ anchor=north
        , fill=white
        , inner sep=1pt
        , text width=1.2cm
        , align=center
        ] {$\mathrm{IC}\equal q^2$ \\ drift};

  \draw[{Latex[round,scale=0.9]}-]
    (axis cs:10,10) -- (axis cs:13,3)
    node[ anchor=north
        , fill=white
        , inner sep=1pt
        , text width=1.2cm
        , align=center
        ] {$\mathrm{IC}\equal q$ \\ diffusion};

  \draw[{Latex[round,scale=0.9]}-]
    (axis cs:1,2) -- (axis cs:0.75,15)
    node[ anchor=south
        , fill=white
        , inner sep=1pt
        , text width=2.3cm
        , align=center
        ] {$\mathrm{IC}\equal q^2+q$ \\ drift+diffusion};

  \node[fill=white] at (axis cs:1,600)     {moderate (M.I.)};
  \node[fill=white] at (axis cs:22,600)    {strong (S.I.)};
  \node[fill=white] at (axis cs:0.045,600) {weak (W.I.)};
\end{axis}