Method of preferentially etching optically flat mirror facets in InGaAsP/InP heterostructures

Claim 1

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: contacting a predetermined area on a given surface of the semiconductor body with a chemical etchant solution of HCl:HNO 3 =(1:α) for a time period sufficient to expose a crystallographic surface through the alternating layers of the semiconductor body substantially perpendicular to the given surface, α is in the range 1<α≦5, and contacting the exposed crystallographic surface with HCl for a time period sufficient to expose a preferred crystallographic plane as an optically flat mirror facet of the semiconductor heterostructure body.

Claim 2

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: contacting a predetermined area on a given surface of the semiconductor body with a chemical etchant solution of HCl:HNO 3 =(1:α) for a time period sufficient to expose a crystallographic surface through the alternating layers of the semiconductor body substantially perpendicular to the given surface, α is in the range 1<α≦5, and contacting the exposed crystallographic surface with HCl for a time period sufficient to expose a preferred crystallographic plane as an optically flat mirror facet of the semiconductor heterostructure body.

Claim 3

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a material selective chemical etchant for a time period sufficient to expose a portion of a crystallographic surface corresponding to an InGaAsP layer and an abutting InP layer, contacting the exposed crystallographic surface with HCl for a time period sufficient to expose a preferred crystallographic plane corresponding to an exposed InP layer abutting the InGaAsP layer, as an optically flat mirror facet of the semiconductor heterostructure body, the preferred plane being substantially coplanar with the exposed portion of the InGaAsP crystallographic surface, and iterating in sequence the processing step followed by the contacting step.

Claim 4

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a material selective chemical etchant for a time period sufficient to expose a portion of a crystallographic surface corresponding to an InGaAsP layer and an abutting InP layer, contacting the exposed crystallographic surface with HCl for a time period sufficient to expose a preferred crystallographic plane corresponding to an exposed InP layer abutting the InGaAsP layer, as an optically flat mirror facet of the semiconductor heterostructure body, the preferred plane being substantially coplanar with the exposed portion of the InGaAsP crystallographic surface, and iterating in sequence the processing step followed by the contacting step.

Claim 8

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a first chemical etchant for a time period sufficient to expose a first crystallographic surface through the alternating layers of the semiconductor body at a substantially definite slope to the given surface, contacting the exposed crystallographic surface with a second chemical etchant selective of quarternary layers composed of InGaAsP for a time period sufficient to expose InGaAsP portions of a preferred crystallographic plane substantially perpendicular to the given surface, and contacting the exposed crystallographic surface corresponding to the InP layers with HCl for a time period sufficient to expose the InP portions of the preferred crystallographic plane to complete an optically flat mirror facet of the semiconductor heterostructure body.

Claim 9

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a first chemical etchant for a time period sufficient to expose a first crystallographic surface through the alternating layers of the semiconductor body at a substantially definite slope to the given surface, contacting the exposed crystallographic surface with a second chemical etchant selective of quarternary layers composed of InGaAsP for a time period sufficient to expose InGaAsP portions of a preferred crystallographic plane substantially perpendicular to the given surface, and contacting the exposed crystallographic surface corresponding to the InP layers with HCl for a time period sufficient to expose the InP portions of the preferred crystallographic plane to complete an optically flat mirror facet of the semiconductor heterostructure body.

Claim 15

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a first chemical etchant for a time period sufficient to expose a first crystallographic surface through the alternating layers of the semiconductor body at a substantially definite slope to the given surface, contacting the first crystallographic surface with HCl for a time period sufficient to expose a portion of a second crystallographic surface corresponding to an exposed portion of each InP layer substantially perpendicular to the given surface, contacting the first and second crystallographic surfaces with a second chemical etchant selective of layers composed of InGaAsP for a time period sufficient to expose a portion of a preferred crystallographic plane corresponding to an exposed portion of each InGaAsP layer substantially perpendicular to the given surface, and contacting the second crystallographic surface with HCl for a time period sufficient to expose portions of the preferred crystallographic plane corresponding to exposed portions of the InP layers, thereby completing the preferred crystallographic plane as an optically flat mirror facet of the semiconductor heterostructure body.

Claim 16

A method for etching a multilayer semiconductor heterostructure body having alternating layers of InGaAsP and InP on a substrate layer, the method comprising the steps of: processing a predetermined area on a given surface of the semiconductor body with a first chemical etchant for a time period sufficient to expose a first crystallographic surface through the alternating layers of the semiconductor body at a substantially definite slope to the given surface, contacting the first crystallographic surface with HCl for a time period sufficient to expose a portion of a second crystallographic surface corresponding to an exposed portion of each InP layer substantially perpendicular to the given surface, contacting the first and second crystallographic surfaces with a second chemical etchant selective of layers composed of InGaAsP for a time period sufficient to expose a portion of a preferred crystallographic plane corresponding to an exposed portion of each InGaAsP layer substantially perpendicular to the given surface, and contacting the second crystallographic surface with HCl for a time period sufficient to expose portions of the preferred crystallographic plane corresponding to exposed portions of the InP layers, thereby completing the preferred crystallographic plane as an optically flat mirror facet of the semiconductor heterostructure body.