Claims
- 1. A semiconductor element, substantially comprising:a substrate, an underlayer, epitaxially grown on the substrate, made of a first semiconductor nitride including at least one element selected from the group consisting of Al, Ga and In, the dislocation density of the underlayer being set to 1011/cm2 or below, the crystallinity of the underlayer being set to 90 seconds or below in full width at half maximum of X-ray rocking curve at (002) reflection, a carrier moving layer, epitaxially grown on the underlayer, made of a second semiconductor nitride including at least one element selected from the group consisting of Al, Ga and In, the dislocation of the carrier moving layer being set to 1010/cm2 or below, the crystallinity of the carrier moving layer being set to 150 seconds or below in full width at half maximum of X-ray rocking curve at (002) reflection, and a carrier supplying layer, epitaxially grown on the carrier moving layer, made of a third semiconductor nitride including at least one element selected from the group consisting of Al, Ga and In.
- 2. A semiconductor element as defined in claim 1, wherein the underlayer is formed at 1100° C. or over by a MOCVD method.
- 3. A semiconductor element as defined in claim 2, wherein the underlayer is formed at a temperature within 1100-1250° C.
- 4. A semiconductor element as defined in claim 1, wherein the substrate is made of a sapphire single crystal having a surface nitride layer on the main surface of the crystal, and the underlayer is formed on the main surface via the surface nitride layer.
- 5. A semiconductor element as defined in claim 1, wherein the material composition of the first semiconductor nitride constituting the underlayer is varied continuously or stepwisely from the substrate toward the conductive layer.
- 6. A semiconductor element as defined in claim 1, wherein the warp of the semiconductor element is 100 μm or below per 5 cm length.
- 7. A high electron mobility transistor comprising a semiconductor element as defined in claim 1, a source electrode, a drain electrode and a gate electrode which are provided on the semiconductor element.
Priority Claims (3)
Number |
Date |
Country |
Kind |
2000-373039 |
Dec 2000 |
JP |
|
2001-153693 |
May 2001 |
JP |
|
2001-267299 |
Sep 2001 |
JP |
|
CROSS REFERENCE TO RELATED APPLICATION
This application is a division of U.S. application Ser. No. 10/007,099 filed Dec. 4, 2001 now U.S. Pat. No. 6,583,468, the entirety of which is incorporated herein by reference.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
11-340147 |
Dec 1999 |
JP |