Patent ID: 11955546
Assignee: TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. A method for controlling a semiconductor device,
the semiconductor device comprising:
a semiconductor part;
a first electrode provided at a backside of the semiconductor part;
a second electrode provided at a front side of the semiconductor part;
a first control electrode provided between the semiconductor part and the second electrode, the first control electrode being provided inside the semiconductor part and electrically insulated from the semiconductor part by a first insulating portion, the first control electrode being electrically insulated from the second electrode by a first inter-layer insulating film;
a second control electrode provided between the semiconductor part and the second electrode, the second control electrode being provided inside the semiconductor part and electrically insulated from the semiconductor part by a second insulating portion, the first and second control electrodes being arranged in a first direction along a front surface of the semiconductor part, the second control electrode being electrically insulated from the second electrode by a second inter-layer insulating film and electrically isolated from the first control electrode;
a plurality of third control electrodes provided respectively between the first control electrode and the first electrode and between the second control electrode and the first electrode, the third control electrodes each being provided inside the semiconductor part and electrically insulated from the semiconductor part by a third insulating portion, the third control electrodes being electrically insulated respectively from the first and second control electrodes by a fourth insulating portion;
a first interconnect electrically connected to the first control electrode;
a second interconnect electrically connected to the second control electrode; and
a third interconnect connected to the plurality of third control electrodes,
the semiconductor part including a first layer of a first conductivity type, a second layer of a second conductivity type, a third layer of the first conductivity type, and a fourth layer of the second conductivity type,
the first layer extending between the first electrode and the second electrode, the third control electrodes being positioned inside the first layer,
the second layer being provided between the first layer and the second electrode, the second layer facing the first control electrode via the first insulating portion and facing the second control electrode via the second insulating portion,
the third layer being selectively provided between the second layer and the second electrode, the third layer contacting the first insulating portion and being electrically connected to the second electrode,
the fourth layer being provided between the first layer and the first electrode and electrically connected to the first electrode,

the method comprising:
biasing the second electrode to a second potential less than a first potential of the first electrode;
at a first timing, changing a first control voltage applied between the second electrode and the first control electrode from a low level less than a first threshold voltage of the first control electrode to a high level greater than the first threshold voltage;
at the first timing, changing a second control voltage applied between the second electrode and the second control electrode from a low level less than a second threshold voltage of the second control electrode to a high level greater than the second threshold voltage;
at the first timing, increasing a third control voltage applied between the second electrode and the third control electrodes to make a potential of the third control electrode to change from a low level less than the second potential to a high level greater than the second potential;
at a second timing after the first timing, changing the second control voltage from the high level greater than the second threshold voltage to a low level less than the second threshold voltage;
at the second timing, reducing the third control voltage to make the potential of the third control electrode to change from the high level greater than the second potential to a low level less than the second potential; and
at a third timing after the second timing, changing the first control voltage from the high level greater than the first threshold voltage to a low level less than the first threshold voltage.