See also O. Tabata, R. Asahi, H. Funabashi, K. Shimaoka, and S. Sugiyama, Anisotropic etching of silicon in TMAH solutions, Sensors and Actuators, A34, 51-57, 1992
Table from V. Temesvary, S. Wu, W. Hsieh, Y-C Tai, and D. Miu, Design, Fabrication and Testing of Silicon Microgimbals for Super-Compact Ridid Disk Drives, J. Microelectromechanical systems 4, 22.
(TMAH is 15% wt) TMAH TMAH EDP Temperature 80C 90C 95C Etch rate (100) Si (&um/hr) 40 65 90 Si:LPCVD LTO oxide 1190:1 800:1 - Si:2E20/cc B doped Si 27:1 20:1 >500:1 Si:1E21/cc B doped Si 100:1 92:1 >500:1
Author SCHNAKENBERG, U.; Benecke, W.; Lochel, B.; Ullerich, S.; Lange,
P.;
Fraunhofer-Inst. fur Mikrostrukturtech., Berlin, Germany
Title NH/sub 4/OH-based etchants for silicon micromachining:
influence of additives and stability of passivation layers
Source Eurosensors IV '90; Part: Karlsruhe, West Germany; Part: 1-3
Oct. 1990;
Sponsored by: EPS; EUREL; IEEE; et al;
Sensors and Actuators A (Physical);
vol.A25, no.1-3;
Oct. 1990-Jan. 1991 pp.; pp. 1-7 pp.
Abstract Solutions based on ammonium hydroxide and water were
investigated for anisotropic etching of monocrystalline
silicon. In 2.65 M NH/sub 3/ solutions at 80 degrees C, the
addition of H/sub 2/O/sub 2/ in a concentration between 0.
65*10/sup -2/ M and 1.84*10/sup -2/ M increases the silicon
etch rate in the (100) direction to 75 mu m/h, which is a
factor of about 2.5 higher compared to pure etchants. In
addition, when the pH value was adjusted above 11.3, silicon
etching proceeds in H/sub 2/O/sub 2/-doped solutions without
formation of pyramidal-shaped hillocks. The influence of the
pH value and H/sub 2/O/sub 2/ concentration on the etching
behaviour is discussed in detail. Passivation layers, like
silicon oxides and silicon nitrides formed under various
preparation conditions, and metals show excellent stability in
AHW solutions. The temperature dependence of etch rates as
well as the influence of post-treatments on the etching
behaviour is discussed
Author SCHNAKENBERG, U.; Benecke, W.; Lochel, B.;
Fraunhofer-Inst. fur Mikrostrukturtech., Berlin, West Germany
Title NH/sub 4/OH-based etchants for silicon micromachining
Source 5th International Conference on Solid-State Sensors and
Actuators and Eurosensors III; Part: Montreux, Switzerland; Pa
rt: 25-30 June 1989;
Sponsored by: Swiss Soc. Sensor Technol.; IEEE;
Sensors and Actuators A (Physical);
vol.A23, no.1-3;
April 1990 pp.; pp. 1031-5 pp.
Abstract Wet chemical etchants based on ammonium hydroxide-water (AHW)
solutions for micromachining monocrystalline silicon are
described. The etchants can be applied under clean-room
conditions within standard IC fabrication lines. The nature of
AHW solutions is discussed with respect to anisotropy and
selectivity. At 75 degrees C and 9 wt.% AHW, a maximum etch
Si/sub 3/N/sub 4/ and highly boron-doped silicon. Aluminium
will not be attacked by silicon-doped AHW etchants. Therefore,
standard IC metallization techniques can be used for device
fabrication. The application of AHW solutions to the
fabrication of basic micromechanical structures is demonstrated