next up previous
Next: 4.1.1.6 Contributions to Up: 4.1.1 The Basic Model Previous: 4.1.1.4 Contributions to the

4.1.1.5 Contributions to $ {\it R}_{\mathrm{gs}}$ and $ {\it R}_{\mathrm{gd}}$.

The ohmic resistances $ {\it R}_{\mathrm{gs}}$ and $ {\it R}_{\mathrm{gd}}$ represent a rather macroscopic and concentrated form of the carrier transport near the gate contact. Due to the strongly locally varying carrier concentrations with a depleted barrier layer n$ \leq$ $ 10^{10}$ cm$ ^{-3}$ and a channel with n$ \geq$ $ 10^{18}$ cm$ ^{-3}$, and carrier temperatures near the gate of $ {\it T}_\mathrm{\nu}$$ \geq$ 10$ \times $ $ {\it T}_\mathrm{L}$ a direct physical interpretation is not suitable as the transport situation is extremely non-linear and thus non-ohmic. However, the information contained in the extraction is to be understood in a behavioral sense. As both a current $ {\it I}_{\mathrm{G}}$ and the voltages $ {\it V}_{\mathrm{GS}}$ and $ {\it V}_{\mathrm{GD}}$ are available, the effective impedances $ {\it R}_{\mathrm{gs}}$ and $ {\it R}_{\mathrm{gd}}$ can be calculated. Especially $ {\it R}_{\mathrm{gs}}$ does supply a high amount information, e.g. for compact noise modeling [230].


Quay
2001-12-21