Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
2006-05-02
2006-05-02
Wilczewski, Mary (Department: 2822)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S270000, C438S272000
Reexamination Certificate
active
07037788
ABSTRACT:
By improving profile of impurity concentration in a channel portion of an FET or an IGBT of a trench gate type, variation of threshold value is lessened, and a destruction caused by current concentration is prevented while suppressing deterioration of cut-off characteristics. An island of a base region of p-type is formed in a semiconductor substrate of n-type by carrying out high acceleration ion implantation twice followed by annealing, so that the impurity concentration profile in a channel portion changes gradually in a depth direction. Accordingly, it is possible to lessen variation of the threshold value and to reduce pinch resistance while at the same time improving sub-threshold voltage coefficient and conductance characteristics.
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Arakawa Takafumi
Ito Hiroyasu
Kato Masatoshi
Denso Corporation
Posz Law Group , PLC
Thomas Toniae M.
Wilczewski Mary
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