Semiconductor device and method for producing semiconductor device
The present invention provides a memory structure including a resistance-changing storage element, which enables a reset operation with a reset gate and in which cross-sectional areas of a resistance-changing film and a lower electrode in a current-flowing direction can be decreased. The semiconductor device of the present invention comprises a first pillar-shaped semiconductor layer, a gate insulating film formed around the first pillar-shaped semiconductor layer, a gate electrode made of a metal and formed around the gate insulating film, a gate line made of a metal and connected to the gate electrode, a second gate insulating film formed around an upper portion of the first pillar-shaped semiconductor layer, a first contact made of a second metal and formed around the second gate insulating film, a second contact which is made of a third metal and which connects an upper portion of the first contact to an upper portion of the first pillar-shaped semiconductor layer, a second diffusion layer formed in a lower portion of the first pillar-shaped semiconductor layer, a pillar-shaped insulating layer formed on the second contact, a resistance-changing film formed around an upper portion of the pillar-shaped insulating layer, a lower electrode formed around a lower portion of the pillar-shaped insulating layer and connected to the resistance-changing film, a reset gate insulating film that surrounds the resistance-changing film, and a reset gate that surrounds the reset gate insulating film.
1. A method for producing a device, comprising:
depositing an interlayer insulating film, forming a contact hole, depositing a metal, and depositing a nitride film;
removing portions of the metal and the nitride film on the interlayer insulating film to form a pillar-shaped nitride film layer and a lower electrode in the contact hole, the lower electrode surrounding a bottom portion of the pillar-shaped nitride film layer and the pillar-shaped nitride film layer;
etching back the interlayer insulating film to expose an upper portion of the lower electrode that surrounds the pillar-shaped nitride film layer;
removing an exposed upper portion of the lower electrode that surrounds the pillar-shaped nitride film layer;
depositing a resistance-changing film so that the resistance-changing film surrounds the pillar-shaped nitride film layer and is connected to the lower electrode;
etching the resistance-changing film to make the resistance-changing film remain as a side wall on an upper portion of the pillar-shaped nitride film layer;
forming a reset gate insulating film so that the reset gate insulating film surrounds the resistance-changing film; and
forming a reset gate.