Pseudomorphic HEMT having strained compensation layer

A high electron mobility transistor comprising:

• substrate means comprising a material having a first lattice constant characteristic for supporting a semiconductor active region;
• a strain compensation layer disposed between said semiconductor active region and said substrate means said strain compensation layer comprised of a material having a second lattice characteristic which when disposed over said substrate means provides said strain compensation layer having a first intrinsic lattice strain characteristic;
• said semiconductor active region comprising:
• a channel layer comprised of a narrow band Group III-V material different from the material of the strain compensation layer, said material having a third, different lattice constant characteristic which when disposed over said strain compensation layer develops a second, different intrinsic lattice strain characteristic opposite to that of the first intrinsic lattice strain characteristic which is compensated by the first intrinsic lattice strain characteristic of the strain compensating layer;
• and
• a charge donor layer comprised of a wide bandgap Group III-V material, said layer disposed to donate charge to said channel layer;
• and
• means for providing ohmic source and drain contacts disposed over said semiconductor active region and a gate electrode disposed on said active region for controlling conduction in said channel layer.