Formation of deep sub-micron buried channel pMOSFETs with plasma doping

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:621327

Felch, S B; Brunco, D P; Lee, B S ^[1]

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1. Varian Research Center, Palo Alto, CA (United States); and others

Plasma Doping (PLAD) is an alternative to conventional beamline ion implantation for the formation of ultra-shallow p{sup +}-n junctions that has been assessed and researched at Varian for several years. In the PLAD process, the silicon wafer to be implanted is placed directly in a plasma containing the desired dopant ions. The wafer is then pulse-biased to a negative potential to accelerate positive dopant ions toward and into the silicon surface. Most of Varian`s work to date has used BF{sub 3} source gas and wafer biases of -0.5 to -5 kV to implant boron into 150-mm and 200-mm wafers to form ultra-shallow p{sup +}-n junctions. Formation of the ultra-shallow junction depths that are predicted to be needed for 0.18 {mu}m technologies (i.e. 60 nm) has been verified by SIMS measurements. Good within-wafer uniformities and wafer-to-wafer repeatability have also been obtained. Deep sub-half micron buried channel pMOSFETs doped at -3.5 kV had excellent threshold voltage roll-offs and off-current leakages, high punchthrough resistances, and very good junction leakage characteristics. These results together with the expected small footprint and low cost-of-ownership of such a system make Plasma Doping an attractive doping technique.

• OSTI ID: 621327
• Report Number(s): CONF-9606110--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON IONS
ION IMPLANTATION
MOSFET
P-N JUNCTIONS
PLASMA
SILICON