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Structures And Layout of a New Self-Aligned Pillar CMOS Logic Gate And SRAM Cell

IP.com Disclosure Number: IPCOM000099657D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 85K

Publishing Venue

IBM

Related People

Dhong, SH: AUTHOR [+3]

Abstract

Disclosed are two applications of the proposed self- aligned pillar CMOS transistor technology. The pillar CMOS devices can be designed to perform a wide variety of logic and memory functions. The advantages of using pillar CMOS technology will be disclosed in the following two examples:

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Structures And Layout of a New Self-Aligned Pillar CMOS Logic Gate And SRAM Cell

       Disclosed are two applications of the proposed self-
aligned pillar CMOS transistor technology.  The pillar CMOS devices
can be designed to perform a wide variety of logic and memory
functions.  The advantages of using pillar CMOS technology will be
disclosed in the following two examples:

      (1) Pillar CMOS NAND Gate:  A pillar CMOS NAND gate is obtained
by connecting NMOS drivers in series whereas the corresponding PMOS
loads are placed in parallel.  The cross section and the
corresponding layout of a NAND  gate are shown in Figs. 1 and 2,
respectively.  The inputs, outputs and interconnections in this gate
use the first level metal and polysilicon as connections as shown in
Fig. 2.  A small layout area results.  Similarly, a pillar CMOS NOR
gate can be implemented.  The combinations of NAND and NOR
configurations can be interconnected to perform a variety of logic
functions as in a gate array.

      2) Pillar CMOS SRAM Cell:  A new SRAM cell can be implemented
with this new pillar CMOS technology.  The cell consists of four NMOS
and two PMOS loads.  The cross section and layout of a SRAM cell are
shown in Figs. 3 and 4, respectively.  A nitride barrier is used to
isolate two NMOS and PMOS transistor regions.  In this cell design,
the vertical nitride barrier region is formed in an L-shape. The
layout of the cross-coupled pair of the cell is done with a...