Fabrication of semiconductor devices utilizing bombardment-enhanced etching of insulating layers

Claim 2

In a method of fabricating a semiconductor device, the steps comprising: forming a layer of thermally grown silicon dioxide on a surface of a body of semiconductor material; selectively bombarding said layer with electrons to provide a charge density on at least a first portion of said layer of from about 0.5 to 1.0 coulomb per square centimeter subjecting said layer after bombarding to an etchant to remove said layer in at least the first portion and to leave remaining at least a second portion, said portions being defined by the pattern of bombarding radiation.

Claim 3

In a method of fabricating a semiconductor device, the steps comprising: forming a layer of insulating material on a surface of a body of semiconductor material, said layer of insulating material comprising at least one oxide of silicon selected from the group consisting of silicon dioxide and silicon monoxide and having a density within the range of at least about 2.18 g./cm3; selectively bombarding said layer with electrons having an energy of from about 0.75* K. to about 1.25* K. for each thousand angstroms of oxide layer to provide a charge density on at least a first portion of the layer of from about one-half coulomb per square centimeter to about 1 coulomb per square centimeter subjecting said layer after bombarding to an etchant to remove said layer in at least a first portion and to leave remaining at least a second portion, said portions being defined by the pattern of bombarding radiation.

Claim 4

In a method of fabricating a semiconductor device, the steps comprising: forming a layer of insulating material on a surface of a body of semiconductor material; selectively bombarding said layer with electrons to provide a charge density on at least a first portion of said layer of from about one-half to about 1 coulomb per square centimeter, said electrons being produced by an electron beam controllably scanned over said layer; subjecting said layer after bombarding to an etchant to remove said layer in at least the first portion and to leave remaining at least a second portion, said portions being defined by the pattern of bombarding radiation.

Claim 5

In a method of fabricating a semiconductor device, the steps comprising: thermally oxidizing a surface of a body of monocrystalline silicon to form a layer of silicon dioxide thereon of a uniform first thickness; selectively bombarding said silicon dioxide layer with electrons with an energy of from about 3/4 * to 1 1/4 * K. for each 1, 000 Angstroms of said silicon dioxide layer anD in sufficient number to provide a charge density on said layer of from about one-half to 1 coulomb per square centimeter; subjecting said layer after bombarding without an etch resistant mask, to an etchant that etches said first portion at a faster rate than at least a second portion of said layer not bombarded by said electrons, said second portion surrounding said first portion; permitting etching to continue until said first portion of said layer is removed and said second portion is reduced in thickness to a second thickness; diffusing an impurity through said first window into said body to form a first PN-junction therein; reforming by thermal oxidation, said layer to provide a third thickness in the location of said first opening, said second thickness being increased and being greater than said third thickness; selectively bombarding said silicon dioxide layer a second time with electrons of an energy to produce ionization within at least a third portion of said layer that is of said third thickness; subjecting said layer after bombarding said second time, without an etch-resistant mask, to said etchant, and permitting etching to continue until said third portion of said layer is removed and a fourth portion surrounding said third portion and not bombarded is reduced in thickness to a fourth thickness to define a second window through said layer.