Optimized double heterojunction pseudomorphic InP/InxGa 1-xAs/InP (0.64⩽x⩽0.82)p-MODFETs and the role of strain in their design

The design and DC and RF characteristics of double heterojunction pseudomorphic In_xGa_1-xAs/InP (0.64 ⩽x⩽0.82) p-type MODFETs are reported. After optimizing the layer sequence in a structure with 64%, In-mole fraction, in order to suppress the parallel conduction in the doping layers, three structures with increased strain (x=0.73, 0.77, and 0.82) were created taking into account the critical channel thickness according to the mechanical equilibrium model and the a priori predicted doping layer thickness. The latter was found to be strongly affected by the strain in the channel. A very good agreement between predicted and measured results was observed. The new structures showed very good performance, indicating high modulation efficiencies