To obtain a vertical working sectional form by making a mixture gas as etchant to form a step at a work by dry etching method contain the mixture gas, which has at least one nitrogen atoms of nitrogen gas, ammonium gas, nitrogen dioxide gas, or the like.
The pattern of an SiO2 mask 1 is made on an n-type lnP substrate 2, using a heat CVD method and a lithography technique. Next, this water is placed on the cathode electrode of an etching device which has parallel board type of electrode structure, and the mixture gas of methane and hydrogen is introduced into an etching processor, and it is supplied with high-frequency power, where an electrode on which a sample is placed is a cathode to cause glow discharge, whereby reactive ion etching is performed to make a step at the substrate. Since the reactive gas contains nitrogen gas, a nitride 3 accumulates on the sidewall of etching, and side etching does not occur, and vertical sectional form is obtained. As compared with the case where nitrogen is not added, superior dimensional controllability can be obtained.
MIYAZAKI MASARU
UOMI KAZUHISA
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