Compound semiconductor device formed of nitrogen-containing gallium compound such as gan, algan or ingan

A gallium nitride (GaN)-based semiconductor light emission device comprising:

• an active layer formed to effect laser oscillation;
• a p-type cladding layer provided near said active layer;
• and
• an n-AlGaN cladding layer provided near said active layer such that said active layer is interposed between said p-type cladding layer and said n-AlGaN cladding layer, Mg being added to said n-AlGaN cladding layer as impurities at a concentration of 10.sup.19 cm.sup.-3 or more.

A gallium nitride (GaN)-based semiconductor device comprising:

• a substrate;
• a buffer layer epitaxially grown in contact with the substrate;
• at least one AlGaN layer epitaxially grown above said buffer layer;
• and
• at least one single-crystal GaN layer epitaxially grown near said substrate and having a thickness less than a critical film thickness,
• wherein the total thickness of said AlGaN layer or layers is more than half the total thickness of all epitaxial layers grown on said substrate.

A gallium nitride (GaN)-based semiconductor device comprising:

• a substrate;
• and either (1):
• a first buffer layer formed on said substrate and not being made from a single-crystal;
• a second buffer layer formed on said first buffer layer which is a single-crystal layer consisting mainly of GaN with a magnesium (Mg) concentration of N.sub.bg1 cm.sup.-3, the single-crystal layer having a thickness of d.sub.1 .mu.m;
• a semiconductor layer consisting mainly of Ga.sub.1-x Al.sub.x N having an Al composition x of at least 0.02 and not higher than 1 and having a thickness of d.sub.2 .mu.m, said single-crystal layer being situated between said substrate and said semiconductor layer, and Mg being added to said semiconductor layer at a concentration of N.sub.Mg cm.sup.-3, and
• an active layer situated between said single-crystal layer and said semiconductor layer and formed to effect laser oscillation;
• wherein said Al composition x, said concentration N.sub.Mg, said concentration N.sub.bg1, said thickness d.sub.1 and said thickness d.sub.2 have the following relationship:
• d.sub.1 /(1600.times.x)<d.sub.2 <3.6.times.10.sup.-3 .times.logN/(x+0.02)+0.02
• wherein when N.sub.Mg >N.sub.bg1, Ncm.sup.-3 =N.sub.Mg -N.sub.bg1, and when N.sub.Mg .ltoreq.N.sub.bg1, N is equal to an Mg background level in additive-free Ga.sub.1-x Al.sub.x N,
• or (2):
• a first buffer layer formed on said substrate and not being made from a single-crystal;
• a second buffer layer formed on said first buffer layer which is a single-crystal layer consisting mainly of GaN with a silicon (Si) concentration of N.sub.bg2 cm.sup.-3, the single-crystal layer having a thickness of d.sub.1 .mu.m;
• and
• a semiconductor layer consisting mainly of Ga.sub.1-x Al.sub.x N having an Al composition x of at least 0.02 and not higher than 1 and having a thickness of d.sub.2 .mu.m, said single-crystal layer being situated between said substrate and said semiconductor layer, and Si being added to said semiconductor layer at a concentration of N.sub.Si cm.sup.-3,
• wherein said Al composition x, said concentration N.sub.Si, said concentration N.sub.bg2, said thickness d.sub.1 and said thickness d.sub.2 have the following relationship:
• d.sub.1 /(1600.times.x)<d.sub.2 <3.2.times.10.sup.-3 .times.logN'/(x+0.02)+0.02
• wherein when N.sub.Si >N.sub.bg2, N' cm.sup.-3 =N.sub.Si -N.sub.bg2, and when N.sub.Si .ltoreq.N.sub.bg2, N' is equal to an Si background level in additive-free Ga.sub.1-x Al.sub.x N.