Abstract
A new 
system has been developed that is particularly suitable for use in etching solutions of 
and 
heterostructure wafers. This system provides high quality etched surfaces without any undesirable roughness or etch pits. Etching rates for 
vary from 0.1 to 10 μm/min, depending on the component proportion of the solutions and/or on the normal of 
aqueous solution. Mesa‐shaped structures have been formed on etching stripes in 
parallel to the [110] and [110] directions. The etchant system has almost equal etching rates for both 
and 
, and thus provides desirable mesa‐shaped structure with high quality etched surfaces and with good resist‐pattern definitions. The solution does not erode photoresists, and is thereby attractive for a variety of device applications.