High Electron Mobility Field-Effect Transistor.

摘要

A semiconductor device comprises at least first and second semiconductor layers (22, 23) to form a hetero joint for constituting a carrier-transmitting area, means (26) for controlling carriers, and means (31, 32) for transmitting and receiving carriers. The semiconductor layer formed between said means (31, 32) for transmitting and receiving carriers has an area containing only 10<1><6>cm<-><3> or less of an impurity. The first semiconductor layer (22) has a wider forbidden band than the second semiconductor layer (23). At least one semiconductor layer (24) having a higher activation efficiency of the impurity is prepared on the one-side surface of the first semiconductor layer (22) in contact with the second semiconductor layer (23) and on the other side area. A multi-quantum well structure may be used as the higher impurity activation efficiency semiconductor layer. The electric resistance in the semiconductor area constituting the carrier-transmitting and receiving means (31, 32) can be lowered.