US5108947A — Integration of gaas on si substrates

Claim 1

Independent Claim 116 words

In a method for depositing a GaAs crystal layer on a Si substrate, the improvement of controlling the formation of microcracks in said layer by confining such microcracks to at least one predetermined location in said crystal layer by the step comprising prior to the deposition, partially covering said substrate by a mask leaving a generally geometrically shaped window on said Si substrate uncovered for deposition thereon of said crystal layer, said mask defining a boundary around said uncovered window region and including at at least one said predetermined location at least one sharp point projecting into said window region at least approximately in a cleavage direction of the subsequently deposited crystal of said GaAs layer.

Claim 2

Dependent Claim 116 words

In a method for depositing a GaAs crystal layer on a Si substrate, the improvement of controlling the formation of microcracks in said layer by confining such microcracks to at least one predetermined location in said crystal layer by the step comprising prior to the deposition, partially covering said substrate by a mask leaving a generally geometrically shaped window on said Si substrate uncovered for deposition thereon of said crystal layer, said mask defining a boundary around said uncovered window region and including at at least one said predetermined location at least one sharp point projecting into said window region at least approximately in a cleavage direction of the subsequently deposited crystal of said GaAs layer.

Claim 3

Dependent Claim 49 words

The method of claim 1, wherein said generally geometrically shaped region has two generally opposite sides and at least one pair of said sharp points are defined by said mask, the points of each pair being situated on two opposite sides of said region at generally opposite predetermined locations.

Claim 4

Dependent Claim 33 words

The method of claim 1, wherein said mask includes a portion disposed in the interior of said window region and at least one such sharp point is defined by the interior mask portion.

Claim 5

Dependent Claim 22 words

The method of claim 1, wherein at least one such sharp point is located on the outside boundary of said window region.

Claim 6

Dependent Claim 27 words

A method according to claim 1 wherein said mask is obtained by deposition of SiO 2 on said Si substrate followed by photolithography and wet chemical etching.

Claim 7

Dependent Claim 20 words

A method according to claim 1 wherein GaAs is deposited by means of the metal organic chemical vapour deposition technique.

Claim 8

Dependent Claim 39 words

A method according to claim 1 wherein in an opening in said mask wherein GaAs is deposited a second mask configuration is provided having at least one such sharp point directed approximately in a cleavage direction of GaAs crystals.

Claim 9

Dependent Claim 144 words

In a method of forming an integrated electronic device in at least one defined region of a GaAs crystal layer having an area larger than said region which layer is grown on a masked Si substrate at a given temperature and subsequently cooled, whereby microcracks are formed in said GaAs layer upon such cooling, the improvement of deliberately inducing microcrack formation at at least one location in said GaAs layer outside each such defined region by means of at least one sharp notch created in a side wall of said layer by means of at least one corresponding sharp point provided by said mask at at least one location spaced form said defined region and extending approximately in a cleavage direction of said layer to initiate microcrack formation at said notch whereby said device is not affected by the presence of any such microcracks.

Claim 10

Dependent Claim 144 words

In a method of forming an integrated electronic device in at least one defined region of a GaAs crystal layer having an area larger than said region which layer is grown on a masked Si substrate at a given temperature and subsequently cooled, whereby microcracks are formed in said GaAs layer upon such cooling, the improvement of deliberately inducing microcrack formation at at least one location in said GaAs layer outside each such defined region by means of at least one sharp notch created in a side wall of said layer by means of at least one corresponding sharp point provided by said mask at at least one location spaced form said defined region and extending approximately in a cleavage direction of said layer to initiate microcrack formation at said notch whereby said device is not affected by the presence of any such microcracks.

Claim 11

Dependent Claim 57 words

The method of claim 8, wherein at least one pair of such notches is created in the side walls of said layer, the notches of each such pair being situated at generally opposite locations on said layer side walls outside said defined region, whereby any microcrack extends between the apices of the notches of one such pair.

Claim 12

Dependent Claim 109 words

A method according to claim 8, wherein prior to the growth of said GaAs crystal layer said Si substrate is partially covered by means of a mask to leave uncovered a window of said Si substrate encompassing said defined region for reception of said crystal layer thereon, said mask being configured with a sharp point at at least one locus along its boundary which point projects interiorly of said uncovered window area in a cleavage direction of the crystals of the subsequently grown GaAs layer to thereby create said sharp notch in side wall of the GaAs layer, said locus being outside the defined region of the electronic device.

Claim 13

Dependent Claim 61 words

A method according to claim 8, wherein said mask is obtained by deposition of a layer of SiO 2 on said Si substrate following by photolithography and wet chemical etching to remove at least one selected window portion of said SiO 2 layer to expose at least one corresponding underlying area of said substrate for reception of the GaAs layer thereon.

Claim 14

Dependent Claim 24 words

The method of claim 8, wherein at least one such sharp notch is created in an exterior side wall of said GaAs crystal layer.

Claim 15

Dependent Claim 42 words

The method of claim 8, wherein said GaAs crystal layer has an interior opening therein defining an interior side wall of said crystal layer and at least one such sharp notch is created in said interior side wall of said crystal layer.

Claim 16

Dependent Claim 20 words

A method according to claim 8 wherein GaAs is deposited by means of the metal organic chemical vapour deposition technique.

Claim 17

Dependent Claim 39 words

A method according to claim 8 wherein in an opening in said mask wherein GaAs is deposited a second mask configuration is provided having at least one such sharp point directed approximately in a cleavage direction of GaAs crystals.

Claim 18

Independent Claim 101 words

A method of controlling the formation in a GaAs crystal layer deposited on a predetermined generally geometrically shaped window area of a masked Si substrate of microcracks caused during cooling after said deposition by differences in the thermal coefficient of expansion of said layer and substrate, which comprises forming by means of a sharp point provided by said mask at at least one locus along the side walls of said shaped GaAs crystal layer an inwardly extending sharp notch directed substantially along one cleavage direction of said GaAs layer, whereby any such microcrack originates at the point of one such notch.

Claim 19

Independent Claim 101 words

A method of controlling the formation in a GaAs crystal layer deposited on a predetermined generally geometrically shaped window area of a masked Si substrate of microcracks caused during cooling after said deposition by differences in the thermal coefficient of expansion of said layer and substrate, which comprises forming by means of a sharp point provided by said mask at at least one locus along the side walls of said shaped GaAs crystal layer an inwardly extending sharp notch directed substantially along one cleavage direction of said GaAs layer, whereby any such microcrack originates at the point of one such notch.

Claim 20

Dependent Claim 47 words

The method of claim 16, wherein one such notch is provided at each of at least one pair of generally opposite loci on the side walls of said shaped layer area, whereby any such microcrack extends between the point of notches at such opposite pairs of loci.

Claim 21

Dependent Claim 42 words

The method of claim 16, wherein said shaped GaAs layer has an interior opening therein defining an interior side wall of said crystal layer and at least one such sharp notch is created in said interior side wall of said crystal layer.

Claim 22

Dependent Claim 23 words

The method of claim 16, wherein at least one such sharp notch is created in an exterior side wall of said crystal layer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-04-28	1995-10-28	1996-04-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-04-28	1999-10-28	2000-04-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-04-28	2003-10-28	2004-04-28	$7700.00	Window Closed / Lapsed

Integration of gaas on si substrates

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