ZnO crystal growth method, ZnO crystal structure, and semiconductor device using ZnO crystal
AssigneesStanley Electric Co., Ltd., Takafumi Yao
InventorsMichihiro Sano, Takafumi Yao
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Abstract
A ZnO crystal growing method having the steps of: growing a low temperature growth ZnO layer on a sapphire substrate at a temperature lower than a single crystal ZnO growth temperature; thermally processing the low temperature growth ZnO layer at a temperature near to a growth temperature of a high temperature growth single crystal ZnO layer higher than the growth temperature low temperature growth ZnO layer; and growing a high temperature growth single crystal ZnO layer on the low temperature growth ZnO layer at a temperature higher than the growth temperature of the of the low temperature growth ZnO layer. ZnO crystal of good quality with a reduced number of crystal defects can be grown on a sapphire substrate.
Claims16
A ZnO crystal structure comprising:
- (a) a sapphire substrate;
- (b) a low temperature growth ZnO single crystal layer formed on said sapphire substrate at a temperature lower than a conventional single crystal ZnO growth temperature so that in an as -deposited state, said low temperature growth ZnO single crystal layer has grain boundaries that are observable in atomic force microscopy, but shows single crystal characteristics in X-ray detraction or reflection electron beam diffraction, and subjected to a surface planarizing process at a temperature capable of growing single crystals so that the grain size increases and the surface is planarized;
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- (c) a high temperature growth ZnO single crystal layer formed on said low temperature growth ZnO single crystal layer at a temperature suitable for growing a single crystal so that said high temperature growth single crystal layer shows a narrower XRC peak at the same diffraction angle and a lower broad peak of PL spectra than a layer grown without the low temperature growth ZnO single crystal layer.
A semiconductor device comprising:
- (a) a sapphire substrate;
- (b) a low temperature growth ZnO single crystal layer formed on said sapphire substrate at a temperature lower than a conventional single crystal ZnO growth temperature so that in an as -deposited state, said low temperature growth ZnO single crystal layer has grain boundaries that are observable in atomic force microscopy, but shows single crystal characteristics in X-ray defraction or reflection electron beam diffraction, and subjected to a surface planarizing process at a temperature capable of growing single crystals so that the grain size increases and the surface is planarized;
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- (c) a high temperature growth ZnO crystal layer formed on said low temperature growth ZnO single crystal layer at a temperature suitable for growing a single crystal so that said high temperature growth ZnO crystal layer shows a narrower XRC peak at the same diffraction angle and a lower broad peak of PL spectra than a layer grown without the low temperature growth ZnO single crystal layer, said high temperature growth ZnO single crystal layer having a p-n junction made of a first ZnO region having an n-type conductivity doped with Ga or Al and a second ZnO region having a p-type conductivity doped with N.
Dependencies are inferred from the claim text.