MIS-type semiconductor device
AssigneeToyoda Gosei Co., Ltd.
InventorsTohru Oka, Takahiro Sonoyama, Kiyotaka Mizukami
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Abstract
The present invention provides a MIS-type semiconductor device having a ZrOxNy gate insulating film in which threshold voltage shift is suppressed, thereby achieving stable operation. In the MIS-type semiconductor device having a gate insulating film on the semiconductor layer and a gate electrode on the gate insulating film, with a gate applied voltage of 5 V or more, the gate insulating film is formed of ZrOxNy (x and y satisfy the relation: x>0, y>0, 0.8≦y/x≦10, and 0.8≦0.59x+y≦1.0). The MIS-type semiconductor device having such a gate insulating film can perform stable operation because there is no shift in the threshold voltage even if a high voltage is applied to the gate electrode.
Claims16
A MIS-type transistor comprising:
- a gate insulating film formed of ZrOxNy on a semiconductor layer and a gate electrode on the gate insulating film, with a gate applied voltage of 5 V or more,
- wherein an oxygen composition ratio x and a nitrogen composition ratio y of the gate insulating film satisfy x>0, y>0, 0.8≦y/x≦10, and 0.8≦0.59x+y≦1.0,
- wherein a ZrOuNv surface layer is continuously formed on and directly contacted with the gate insulating film and an oxygen composition ratio u of the ZrOuNv surface layer is higher than the oxygen composition ratio x of the gate insulating film, and the ZrOuNv surface layer directly contacts the gate electrode,
- wherein the oxygen composition ratio u of the ZrOuNv surface layer is continuously increased as it is closer to the gate electrode in a thickness direction, and
- wherein the nitrogen composition ratio v of the ZrOuNv surface layer is continuously decreased as it is closer to the gate electrode in a thickness direction.
Dependencies are inferred from the claim text.