A New Etching Solution System,  H 3 PO 4 ‐  H 2 O 2 ‐  H 2 O  , for GaAs and Its Kinetics

Abstract

A new solution system consisting of H3PO4, H202, and H20 was found useful for etching GaAs wafers. This solution system can be divided into four regions a-d, according to etching characteristics. The boundaries between the regions are given by a rfiole ratio (m 9 r) of H202 to HsPO4 of about 2.3 and a mole fraction (m 9 5) of H20 of about 0.9 at room temperature. Ratelimiting processes are: a, adsorption of H202 (m. r <_ 2.3, m. ] ~ > 0.9)', b, diffusion of H202 (m 9 r <~ 2.3, m 9 ] < 0.9) ; c, dissolution of oxidized products (m-r > 2.3, m-] <_ 0.9); and d, adsorption of H~PO~ (~-r _ > 2.3, m. ] > 0.9). Solutions in region a have a reproducible etching rate of 0.01-0.1 ~m/min, which is useful for MESFET processing. Crystallographic etching is also available with solutions in region c.

The Influence of Native Oxide Layers of InP on the Shape of Etching Profiles at Resist Edges

“…3]. This is in agreement with the considerations given by Mort and Watanabe (7). That a gradual transition from kinetically controlled to diffusion-controlled etching occurred in this temperature range could also be deduced from the fact that, on going from lower to higher temperature, the length of the (111)In facet in the profiles strongly decreased, ultimately disappearing at the highest temperature.…”

“…F r o m t h e slope of this line a n activation e n e r g y of 41 x 103 J 9 mo1-1 is calculated. This value is typical ofkinetically c o n t r o l l e d p r o c e s s e s (7). T h e a g r e e m e n t of t h e etch rate of this p l a n e in t h e e t c h e d profiles a n d t h e chemical e t c h rate of t h e m a c r o s c o p i c p l a n e at t h e s a m e t e m p e r ature as d e t e r m i n e d in (4) is excellent.…”

“…However, the slope of this line is much lower than that found for kinetically controlled reactions. This is expected for a diffusion-controlled process (7). From the slope, an activation energy of 15 x 103 J 9 mol 1 is calculated.…”

Fabrication of deep vias/grooves as interconnection path by wet etching for wafer level packaging of GaAs based image sensor

“…GaAs wet etching has been reported since 1972 by Shinya Lida [1] and constantly reported for different applications with different etching system [2][3][4]. Till now many etching system has been developed such as acid based system [5][6], NH 4 OH system [7], K 2 Cr 2 O 7 system [8].…”

Anisotropic Chemical Etching of III—V Crystals Dissolution Slowness Surface and Application to GaAs

“…Effectively several studies [7][8][9][10][11][12][13][14] have shown that the chemical etching of GaAs in various etchants is anisotropic. In the micromachining of mechanical devices the anisotropy provides reproducible shapes because structures are often limited by crystallographic planes.…”