Single Crystal Silicon MEMS Fabrication Technology Using
Proton-Implantation Smart-Cut Technique
Darrin J. Young,
Wen H. Ko
EECS Department, Case Western Reserve University
Cleveland, Ohio, USA
A novel single crystal silicon MEMS fabrication process is
proposed using proton-implantation smart-cut technique.
Compared to conventional SOI wafer fabrication processes
for MEMS applications, this technology can potentially
result in a significant substrate and processing cost reduc-
tion. A single crystal silicon layer with 1.78
has been achieved using the proposed technique. Prototype
structures such as cantilever beams and clamped-clamped
micro-bridges have been successfully fabricated as demon-
stration vehicles for future micro-system implementations.
MEMS; micromachining; single crystal silicon; smart-cut;
wafer splitting; proton implantation.
Single crystal silicon material is highly desirable for im-
plementing MicroElectroMechanical devices and systems
due to its reliable and reproducible mechanical and electri-
cal properties. Silicon on insulator (SOI) wafers have been
used to realize single crystal silicon MEMS inertial sen-
sors, optical devices, field emission components, etc. [1, 2,
The silicon structural layer is typically obtained
through wafer bonding followed by a grinding and chemi-
cal mechanical polishing (CMP) step [2, 5].
nique, however, results in a substantial amount of silicon
material loss through the grinding and CMP process, hence
increasing the substrate and processing cost.
In this paper,
we present a novel single crystal silicon MEMS fabrication
technology based on proton-implantation smart-cut tech-
This technique has been proposed to produce low
cost SOI wafers, with a typical silicon thickness on the
order of nanometers, for low power microelectronics appli-
cations [6, 7]. At present most MEMS devices, however,
call for silicon structural layer with a thickness of at least 1
m, sometimes a few tens of micrometers, to achieve cer-
tain performance requirements.
In this research we have
demonstrated that single crystal silicon layer with mi-
crometer thickness can be obtained through increasing the
proton implantation energy using the smart-cut technique
for MEMS applications.
The silicon film thickness, critical
for precision micro-system fabrication, can be accurately
determined through implantation energy control.
more, the proposed fabrication technique eliminates the
grinding and CMP processes required in conventional
MEMS SOI wafer preparation, potentially resulting in a
significant substrate and processing cost reduction. MEMS
prototype structures such as cantilever beams and clamped-
clamped micro-bridges with a silicon thickness of 1.78
have been fabricated as demonstrated vehicles for future