Abstract:
A method of forming a metal gate for a CMOS device using a replacement gate process wherein sidewall spacers are formed on a dummy electrode prior to forming the metal gate allowing source and drain formation prior to metal gate formation and a tungsten layer is selectively deposited to act as an each or CMP stop and to reduce source and drain resistance. The process begins by forming a dummy gate oxide layer and a polysilicon dummy gate electrode layer on a substrate structure and patterning them to form a dummy gate. Lightly doped source and drain regions are formed by ion implantation using the dummy gate as an implant mask. Spacers are formed on the sidewalls of the dummy gate. Source and drain regions are formed by implanting ions using,the dummy gate and spacers as an implant mask and performing a rapid thermal anneal. A tungsten layer is selectively deposited on the dummy gate electrode and the source and drain regions. A blanket dielectric layer is formed over the dummy gate and the substrate structure. The blanket dielectric layer is planarized using a chemical mechanical polishing process stopping on the tungsten layer. The tungsten layer overlying the dummy gate and the dummy gate are removed, thereby forming a gate opening. A gate oxide layer and a metal gate electrode layer are formed in the gate opening. The gate electrode layer is planarized to form a metal gate, stopping on the blanket dielectric layer. Alternatively, the dummy gate electrode can be composed of silicon nitride and the selectively deposited tungsten layer can be omitted.
Abstract:
The present invention discloses a method of fabricating self-aligned cylindrical capacitor in stack Dynamic Random Access Memory (Stack DRAM) cells. The polysilicon stud is filled in the contact window of the source region of a metal-oxide-semiconductor field effect transistor (MOSFET). Then the polysilicon spacers are formed on the sidewalls of the first polysilicon stud. The cylindrical capacitor storage node of the DRAM capacitor of the present invention has much greater surface area so as to increase the capacitance value of the DRAM capacitor, that can achieve high packing density of the integrated circuit devices. Furthermore, this new process only needs one lithography photomask to open contact window compared with the conventional process which needs two lithography photomasks, that further reduces the production cost.
Abstract:
A MOSFET device with a substrate covered with dielectric material with the device including a plurality of buried conductors capacitively coupled to a polysilicon electrode, made by:forming between regions containing MOSFET devices a region with a plurality of bit lines in the substrate by ion implantation through the gate oxide into the substrate in a predetermined pattern and,forming a polysilicon electrode on the dielectric material crossing over the bit lines.
Abstract:
An MOSFET device is fabricated with a plurality of conductors capacitively coupled to a first electrode, forming a mask on the surface of the first electrode exposing a predetermined zone of the first electrode, doping the first electrode through the mask, removing the mask from the surface of the first electrode, oxidizing the first electrode to form a layer of oxide over the first electrode with a thicker layer of oxide over the predetermined zone and a thinner layer of oxide elsewhere, forming at least one electrode over the first electrode on the thinner layer of oxide outside of the zone and forming at least one other electrode over the first electrode on the thicker layer of oxide inside the zone, whereby the one electrode and the other electrode have substantially different capacitive coupling to the electrode.