Title :
Boron sidewall implantation and selective etching of p-doped poly-Si for 1 Gbit DRAM stacked capacitors
Author :
Wendt, H. ; Honlein, W. ; Franosch, M. ; Hasler, B. ; Widmann, D.
Author_Institution :
Corp. Res. & Dev., Siemens AG, Munich, Germany
Abstract :
It is generally accepted that a minimum cell capacitance of about 25 fF is necessary for DRAMs. In order to allow for lateral shrinking of the cell sizes while keeping the required cell capacitance, either trench or stacked capacitors cell concepts were proposed to provide the desired area magnification. Stack type capacitors are formed by taking advantage of different etch rates of various layers of oxides, oxides and poly-Si, or doped/undoped poly-Si. In this work, the authors describe a new process sequence to produce a stacked capacitor which meets the requirements for the production of 1 Gbit DRAMs. They demonstrate the feasibility of fin stack capacitors with mechanically supported fins produced by sidewall implantation and selective etching of p-doped poly-Si. The concept is scaleable to sizes required for 1 Gbit DRAMs.
Keywords :
CMOS memory circuits; DRAM chips; MIS capacitors; VLSI; boron; doping profiles; etching; integrated circuit technology; ion implantation; mechanical stability; silicon; 1 Gbit; 25 fF; B sidewall implantation; DRAM stacked capacitors; Gbit dynamic RAMs; ONO dielectric; SiO/sub 2/-Si/sub 3/N/sub 4/-SiO/sub 2/-Si:B; cell capacitance; fin stack capacitors; mechanically supported fins; p-doped poly-Si; p-doped polysilicon; process sequence; selective etching; Boron; Capacitance; Capacitors; Etching; Production;
Conference_Titel :
VLSI Technology, 1996. Digest of Technical Papers. 1996 Symposium on
Conference_Location :
Honolulu, HI, USA
Print_ISBN :
0-7803-3342-X
DOI :
10.1109/VLSIT.1996.507854