Current Transport in Double Heterojunction HEMTs

Simulations and measurements of a submicron pseudomorphic high electron mobility transistor (HEMT) are presented. For the simulations the generic device simulator MINIMOS-NT [1] is used which is capable of dealing with complex device geometries as well as with several physical models. The simulator allows a simulation of the extrinsic behavior of a HEMT Two different methods of contacting the channel in the simulation are compared, source and drain metal directly contacting the channel versus contact metal only on top of the cap layer. It is shown that one has to include all heterojunctions in the current path to obtain a proper simulation of the transconductance of a HEMT. Moreover, it is shown that hydrodynamic simulation in the channel is also necessary.