Semiconductor device and method of fabrication thereof
AssigneeRenesas Technology Corp.
InventorsYasuki Morino, Yoshihiko Kusakabe, Ryuichi Wakahara
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Abstract
A method includes the steps of: introducing insulation film into a trench to provide a trench isolation; planarizing the trench isolation to expose a passivation film; and removing the passivation film and depositing a second silicon layer on a first silicon layer and the trench isolation; and in the step of depositing the first silicon layer the first silicon layer is an undoped silicon layer and in the step of depositing the second silicon layer the second silicon layer is a doped silicon layer or an undoped silicon layer subsequently having an impurity introduced thereinto or the like and thermally diffused through subsequent thermal hysteresis into the first silicon layer.
Claims7
1-5. (canceled)
A semiconductor device comprising:
- a semiconductor substrate;
- isolating insulation films each filled a trench in said semiconductor substrate and having a portion protruding above said semiconductor substrate;
- a gate insulation film formed between said isolating insulation films on and in contact with said semiconductor substrate;
- a first polysilicon layer formed on and in contact with said gate insulation film;
- and
- a second polysilicon layer formed on said first polysilicon layer, wherein said first polysilicon layer is smaller in crystal grain size than said second polysilicon layer.
Dependencies are inferred from the claim text.