Method of making surface emission type semiconductor laser

Claim 3

A method as defined in claim 1, wherein said etching step is terminated leaving a part of said cladding layer such that an active layer underlying said cladding layer is not exposed.

Claim 4

A method as defined in claim 1, wherein said photoresist mask is formed by subjecting a hard baked photoresist layer to a reactive ion etching process, whereby side walls of said photoresist mask are perpendicular to said semiconductor substrate.

Claim 5

A method as defined in claim 3, wherein said photoresist mask is used to form said at least one column-like portion through a reactive ion beam etching process, whereby the side walls of said at least one column-like portion are perpendicular to said semiconductor substrate.

Claim 6

A method as defined in claim 1, wherein a plurality of said column-like portions are formed by the etching using said photoresist mask and wherein a separation groove is formed between each pair of adjacent column-like portions, said separation groove having a minimum width equal to about 1 μm.

Claim 7

A method as defined in claim 5, wherein said etching step is terminated leaving a part of said cladding layer so that each of said separation grooves will not reach an active layer underlying said cladding layer.

Claim 8

A method as defined in claim 6, wherein said II-VI group compound semiconductor epitaxial layer is transparent to the wavelength of an emitted laser beam and is vapor grown in each of said separation grooves.

Claim 9

A method as defined in claim 3, further comprising the steps of forming a film having a thickness smaller than a thickness of said hard baked photoresist layer on said hard baked photoresist layer, forming a second photoresist layer on said film and forming a resist pattern from said second photoresist layer by a photolithograph step, etching said film through said resist pattern as a mask to form a film mask having sides perpendicular to said semiconductor substrate by a reactive ion etching process, and etching said hard baked photoresist layer through said film mask to form said photoresist mask by a reactive ion etching process.

Claim 10

A method as defined in claim 8, wherein said photoresist mask is used to form said at least one column-like portion by a reactive ion beam etching process and wherein said at least one column-like portion has sides perpendicular to said semiconductor substrate.

Claim 11

A method as defined in claim 8, wherein said film is formed of a material selected from a group consisting of Ti, SiO 2 and SiN.

Claim 12

A method as defined in claim 8, wherein the thickness of said film ranges from 1000 Angstroms to 1 μm.

Claim 13

A method as defined in claim 8, further comprising the steps of previously forming a polycrystalline etching stop layer having an etching rate lower than an etching rate of said II-VI group compound semiconductor epitaxial layer between said multilayered semiconductor layer and said hard baked photoresist layer, forming a polycrystalline II-VI group compound semiconductor layer on said etching stop layer on the vapor growth of said II-VI group compound semiconductor epitaxial layer after said photoresist mask has been removed, said polycrystalline II-VI group compound semiconductor layer protruding beyond said II-VI group compound semiconductor epitaxial layer, forming a layer having a flat surface on said polycrystalline II-VI group compound semiconductor layer and said II-VI group compound semiconductor epitaxial layer, etching said flat layer, said polycrystalline II-VI group compound semiconductor layer and said II-VI group compound semiconductor epitaxial layer and detecting the end of etching depending on the degree of exposure of said etching stop layer so that the surface of said II-VI group compound semiconductor epitaxial layer is etched to be substantially flush with the surface of said at least one column-like portion.

Claim 14

A method as defined in claim 12, wherein the thickness of said etching stop layer is set sufficiently to be exposed when said polycrystalline II-VI group compound semiconductor layer on the etching stop layer is etched and before the surfaces of said at least one column-like portion becomes substantially flush with the surface of said II-VI group compound semiconductor epitaxial layer.

Claim 15

A method as defined in claim 13, wherein said etching stop layer is formed of a material selected from a group consisting of SiO 2 and SiN.

Claim 16

A method as defined in claim 12, wherein said flat layer is formed of a material selected from a group consisting of resist material and polyimide.

Claim 17

A method as defined in claim 1, wherein said photoresist mask is used to form said at least one column-like portion through a reactive ion beam etching process, so that the side walls of said at least one column-like portion are perpendicular to said semiconductor substrate.

Claim 18

A method as defined in claim 1, wherein said II-VI group compound semiconductor epitaxial layer is transparent for a generation wavelength of the surface emission type semiconductor laser.