Method for manufacturing a semiconductor device

DETAILED DESCRIPTION We claim: 1.
A method for manufacturing a semiconductor device including an etching process for selectively removing a semiconductor layer formed on a substrate, said method comprising the steps of implanting into said semiconductor layer an impurity with etching-resistant property relative to an isotropic etching of said semiconductor layer, anisotropic-etching away a region of said semiconductor layer to be selectively etched away with its portion in its thickness direction being remained, and removing said remained portion in said thickness direction of said semiconductor layer by the isotropic etching.
2.
A method for manufacturing a semiconductor device including an etching process for selectively removing a semiconductor layer formed on a substrate, said method comprising the steps of implanting into said semiconductor layer an impurity with etching-resistant property relative to an isotropic etching of said semiconductor layer, anisotropic etching away a region of said semiconductor layer to be selectively etched away with its portion in its thickness direction, being remained diffusing said impurity into a region of said semiconductor layer which is not etched away by annealing, and removing said remained portion in said thickness direction of said semiconductor layer by the isotropic etching.




Description:
DESCRIPTION 1.
Technical Field This invention relates to a method for manufacturing various kinds of discrete semiconductor devices or a semiconductor device such as a semiconductor integrated circuit device and so on.
2.
Background Art Upon manufacturing various kinds of semiconductor devices, there is frequently employed such a process for selectively etching a semiconductor layer such as a polycrystalline semiconductor layer or amorphous semiconductor layer.
With reference to FIGS.
1 to 9, an example of a prior art method for manufacturing a semiconductor device by forming a polycrystalline silicon semiconductor layer on a silicon substrate and then selectively etching the same will be described