Method for manufacturing a layer of gallium nitride or gallium and aluminum nitride
View Patent ↗The present invention relates to a method for manufacturing a crack free monocrystalline nitride layer having the composition Al x Ga 1-x N, where 0≦x≦0.3, on a substrate that is likely to generate tensile stress in the layer and to structures containing such layer and substrate. The method includes forming a nucleation layer on the substrate; forming a monocrystalline intermediate layer of aluminum or gallium nitride at a selected thickness on the nucleation layer; forming a monocrystalline seed layer of an AlBN compound in which the boron content is between 0 and 10% at a selected temperature and thickness on the intermediate layer with the thicknesses of the seed and intermediate layers being in a ratio of between 0.05 and 1; and forming the monocrystalline nitride layer of Al x Ga 1-x N nitride at a selected temperature on the seed layer, with the temperature of formation of the seed layer being 50 to 150° C. higher than the temperature of formation of the monocrystalline nitride layer in order to avoid producing cracks in the monocrystalline nitride layer.
1. A method for manufacturing a crack free monocrystalline nitride layer having the composition Al x Ga 1-x N, where 0≦x≦0.3, on a substrate that is likely to generate tensile stress in the layer, which method comprises:
forming a nucleation layer on the substrate;
forming a monocrystalline intermediate layer of aluminum or gallium nitride at a selected thickness on the nucleation layer;
forming a monocrystalline seed layer of an AIBN compound in which the boron content is between 0 and 10% at a selected temperature and thickness on the intermediate layer with the thicknesses of the seed and intermediate layers being in a ratio of between 0.05 and 1; and
forming the monocrystalline nitride layer of Al x Ga 1-x N nitride at a selected temperature on the seed layer, with the temperature of formation of the seed layer being 50 to 150° C. higher than the temperature of formation of the monocrystalline nitride layer in order to avoid producing cracks in the monocrystalline nitride layer.
2. The method according to claim 1 , wherein the thickness of the monocrystalline nitride layer is between 800 nm and 7 micrometers.
3. The method according to claim 1 , wherein the thickness of the intermediate layer is equal to or greater than 250 nm.
4. The structure method according to claim 3 , wherein seed layer has a thickness of between 30 and 250 nm.
5. The method according to claim 1 , wherein the intermediate layer has an aluminum content of between 1 and 35%.
6. The method according to claim 1 , wherein the thickness ratio of the seed and intermediate layers is between 0.2 and 0.35.
7. The method according to claim 1 , wherein the seed layer is formed by molecular beam epitaxy at a formation temperature that is 80° C. higher than the formation temperature of the monocrystalline nitride layer.
8. The method according to claim 1 , wherein the seed layer presents a relaxation rate, at ambient temperature, of less than 80%.
9. The method according to claim 8 , wherein the relaxation rate of the seed layer is between 50 and 75%.
10. The structure method according to claim 1 , wherein the monocrystalline nitride layer comprises 3 to 5% of aluminum and wherein the method further comprises, forming on the monocrystalline nitride layer:
a gallium nitride channel layer having a thickness of 5 to 100 nm; and
a barrier layer of AlGaN, AlInN or BGaN.
11. The structure method according to claim 1 , wherein the method further comprises, forming on the monocrystalline nitride layer:
a channel layer of ScN; and
a barrier layer of AlGaN, AlInN or BGaN.
12. The structure method according to claim 1 , wherein the monocrystalline nitride layer is gallium nitride and wherein the method further comprises, forming on the gallium nitride layer, a barrier layer of AlGaN, AlInN or BGaN.
13. The method of claim 1 , which further comprises incorporating the layer in a device provided in the form of a photovoltaic component, an electroluminescent diode, a Schottky diode, a laser, an optical detector, or an MEMS.
14. The method of claim 1 , which further comprises incorporating the layer in a field effect transistor.