| 摘要 |
PROBLEM TO BE SOLVED: To improve two-dimensional electron gas mobility by performing the crystal growth of a spacer layer that is inserted between a natural InGaAs layer that becomes an electron running layer and an n-AlGaAs layer that becomes a carrier supply layer with a V/III ratio being equal to or more than a specific value. SOLUTION: A natural AlGaAs buffer layer 2, a natural InGaAs electron running layer 3, a natural AlGaAs spacer layer 4, and an Si-doped n-AlGaAs carrier supply layer 5 are successively formed on a GaAs substrate 1. An HEMT structure epitaxial wafer for evaluating two-dimensional electron gas mobility is allowed to grow by the MOVPE method so that a V/III ratio for allowing the natural AlGaAs spacer layer 4 to grow becomes 110 or higher. Mobility gradually increases until the V/III ratio becomes 110, while the mobility becomes nearly constant when the V/III ratio is equal to or more than 110, thus improving the two-dimensional electron gas mobility of an InGaAs/AlGaAs-family HEMT structure epitaxial wafer.
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