Coorstek Kk

Noriko Omori

Yoshihisa Abe

Hiroshi Oishi

Jun Komiyama

Kenichi Eriguchi

Tomoko Watanabe

There is provided a nitride semiconductor epitaxial substrate having a channel layer, a spacer layer, and an electron supply layer that are stacked in this order. The channel layer is GaN. The spacer layer is AlGaN (0&#x3c;a&#x3c;0.5). The electron supply layer is AllnGaN (0&#x3c;x+y&#x2264;1). The spacer layer has a thickness of two molecular layers or less.

Nitride semiconductor epitaxial substrate

A compound semiconductor substrate according to the present invention includes a compound semiconductor layer formed on one main surface of a ground substrate via a seed layer, wherein the ground substrate is formed of a sintered body, the seed layer is formed of a single crystal, the compound semiconductor layer includes a structure having a buffer layer and an active layer that are sequentially crystal-grown on the seed layer, a thermal expansion coefficient of the sintered body is 0.7 times or more and 1.4 times or less an average thermal expansion coefficient of the entire compound semiconductor layer, and an FWHM of an X-ray diffraction peak of the buffer layer obtained by an X-ray diffraction rocking curve measurement is 800 arcsec or less.

Compound semiconductor substrate

The present invention provides a nitride semiconductor substrate having an initial nitride and a nitride semiconductor sequentially stacked on one principal plane of a base substrate, wherein the nitride semiconductor substrate comprises recesses depressed from an interface between the base substrate and the initial nitride toward the base substrate along one arbitrary cross section; the recesses each have a diameter of 6 nm or more and 60 nm or less and are formed at a density of 3&#xd7;10pieces/cmor more and 1&#xd7;10pieces/cmor less; and the recess preferably has a depth of 3 nm or more and 45 nm or less from the interface between the base substrate and the initial nitride toward the base substrate.

Nitride semiconductor substrate having recesses at interface between base substrate and initial nitride

A solution is formation of a nitride semiconductor layer on one principal plane of a single crystal substrate through a first layer. Upon selecting arbitrary three places in a radial direction from a cross section cleaved in a diameter portion and observing an interface between the first layer and the nitride semiconductor layer by taking a width of at least 500 nm in the radial direction, a value is within the range of 6 nm or more and 15 nm or less in a mean value of the three places with regard to a difference between a maximum height of a convex top portion and a minimum height of a concave bottom portion of the first layer in a thickness direction from the single crystal substrate toward the nitride semiconductor layer. A value is 10 nm or more and 25 nm or less in the mean value.

Growing community of inventors

Hadano, Japan

Noriko Omori