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Planar Fully Integrated Bulk/SOI SiGe CMOS Fabrication Process

IP.com Disclosure Number: IPCOM000107551D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Crabbe, EF: AUTHOR [+4]

Abstract

Disclosed is a process for fabricating both a p-HFET and an n-MOSFET in a single SiGe channel region. The fully-integrated SiGe CMOS fabrication process solves the thermal budget and multi-deposition problems and, furthermore, results in a planar structure at the expense of only one additional mask.

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Planar Fully Integrated Bulk/SOI SiGe CMOS Fabrication Process

       Disclosed is a process for fabricating both a p-HFET and
an n-MOSFET in a single SiGe channel region. The fully-integrated
SiGe CMOS fabrication process solves the thermal budget and
multi-deposition problems and, furthermore, results in a planar
structure at the expense of only one additional mask.

      The disclosed structure can be fabricated in the following
sequence of steps (see the figure):

      Form the dual wells in the Si substrate and follow by the
deposition of a SINGLE SiGe-channel by Low Temperature Epitaxy for
BOTH n-MOSFET and p-HFET. Low thermal cycle Shallow Trench/MESA
Isolation.  The SiGe is passivated with a thin (10 nm) undoped Si epi
layer. The n-well is self-passivated as positive charge in the oxide
on the sidewalls will lead to accumulation. The p-well is passivated
by a double- angled boron implant. A non-critical additional mask
follows to adjust the n-MOSFET threshold voltage. Low temperature
processing is then used to complete the devices, including a single
n+ polysilicon deposition for the gates of both the n-MOSFET and
p-HFET. The resulting n-MOSFET is a surface-channel device and the
p-HFET a sub-surface channel device with holes confined in the
SiGe-channel.

      An acceptable epitaxial profile is as follows: First, a boron-
doped layer is grown with typical concentration and thickness of
4x1017cm3 and 35 nm. Next, an undoped SiGe-channel is grown...