Study of gate length, channel length and gate-source spacing on the GaAs MESFET characteristics

The transconductance (gm) of Gallium Arsenide MEtal Semiconductor Field Effect Transistors(GaAs MESFETs) plays an important role in the performance of high speed logic circuits. It is shown here that the gm is drastically affected by the source resistance. GaAs MESFETs realised on epitaxial wafers using self aligned and non self aligned methods show different gm for the same gate length. The self aligned MESFETs show higher gm than that of non self aligned transistors since the channel resistance is less.