Composition, its use and a process for selectively etching silicon-germanium material

1 . A composition comprising:

(a) 5 to 15% by weight of an oxidizing agent;

(b) 5 to 20% by weight of an etchant comprising a source of fluoride ions;

(c) 0.0005 to 3% by weight of a first selectivity enhancer of formula S1

and

(d) water;

wherein

R S1 is selected from X S —OH and Y S —(CO)—OH;

R S2 is selected from (i) R S1 , (ii) H, (iii) C 1 to C 10 alkyl, (iv) C 1 to C 10 alkenyl, (v) C 1 to C 10 alkynyl, and (vi) —X S1 —(O—C 2 H 3 R S6 ) m —OR S6 ;

R S6 is selected from H and C 1 to C 6 alkyl;

X S is selected from a linear or branched C 1 to C 10 alkanediyl, a linear or branched C 2 to C 10 alkenediyl, linear or branched C 2 to C 10 alkynediyl, and —X S1 —(O—C 2 H 3 R 6 ) m —;

Y S is selected from the group consisting of a chemical bond and X S ;

X S1 is a C 1 to C 6 alkanediyl;

m is an integer of from 1 to 5;

wherein the composition has a pH of from 4 to 8; and

wherein the composition is suitable for selectively etching a first layer comprising a silicon germanium alloy Si x Ge y , wherein x is from 0.70 to 0.90 and y is from 0.10 to 0.30, with x+y=1.00, in the presence of a second layer consisting of silicon,

wherein an etch rate of the composition for the first layer is at least 500 times an etch rate of the composition for the second layer.

2 . The composition according to claim 1 , wherein the oxidizing agent is selected from the group consisting of peroxides.

3 . The composition according to claim 1 , wherein the oxidizing agent is present in an amount of from 7 to 13% by weight.

4 . The composition according to claim 1 , wherein the etchant is selected from the group consisting of hydrogen fluoride, ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine trihydrofluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, tetrabutylammonium tetrafluoroborate and mixtures thereof.

5 . The composition according to claim 1 , wherein the etchant is present in an amount of from 8 to 18% by weight.

6 . The composition according to claim 1 , wherein the first selectivity enhancer is present in an amount of

(a) from 0.0005 to 0.02% by weight, if R S1 is X S —OH, or

(b) from 0.1 to 3% by weight, if R S1 is Y S —(CO)—OH.

7 . The composition according to claim 1 , wherein R S1 is X S —OH and X S is a C 1 to C 8 alkanediyl.

8 . The composition according to claim 7 , wherein the first selectivity enhancer is a compound of formula S2

wherein

R S11 , R S21 are independently selected from the group consisting of a C 1 to C 6 alkyl,

R S12 , R S22 are independently selected from the group consisting of H and a C 1 to C 10 alkyl.

9 . The composition according to claim 1 , wherein the first selectivity enhancer is a compound of formula S3

or, if the first selectivity enhancer is a compound of formula S2, the composition further comprises a second acetylenic compound of formula S3.

10 . The composition according to claim 1 , further comprising an organic acid selected from the group consisting of hydroxy carboxylic acids.

11 . The composition according to claim 1 , further comprising a surfactant of formula F1

wherein

X F2 is a C 1 to C 4 alkanediyl;

R F4 is a C 12 to C 30 alkyl or a C 12 to C 30 alkenyl; and

R F5 is a C 1 to C 4 alkyl.

12 . A method of using the composition of claim 1 , the method comprising using the composition for selectively etching a layer comprising Si x Ge y , wherein x is from 0.70 to 0.90 and y is from 0.10 to 0.30, with x+y=1.00, in the presence of a layer consisting of silicon.

13 . A process of selectively removing a layer comprising a silicon germanium alloy Si x Ge y , wherein x is from 0.70 to 0.90 and y is from 0.10 to 0.30, with x+y=1.00, from a surface of a microelectronic device relative to a layer consisting of silicon, the process comprising:

(a) providing a microelectronic device surface that includes the layer comprising the silicon germanium alloy and the layer consisting of silicon,

(b) providing a composition according to claim 1 , and

(c) contacting the surface with the composition for a time and at a temperature effective to selectively remove the layer comprising silicon-germanium relative to the layer consisting of silicon.

14 . A process for the manufacture of a semiconductor device, comprising the step of selectively removing the layer comprising silicon-germanium from a surface of a microelectronic device relative to the layer consisting of silicon according to claim 13 .

15 . The composition according to claim 1 , wherein the oxidizing agent is hydrogen peroxide.

16 . The composition according to claim 1 , wherein the oxidizing agent is present in an amount of from 8 to 12% by weight.

17 . The composition according to claim 1 , wherein the etchant is hydrogen fluoride.

18 . The composition according to claim 1 , wherein the etchant is present in an amount of from of from 12 to 16% by weight.

19 . The composition according to claim 1 , wherein the first selectivity enhancer is present in an amount of

(a) from 0.001 to 0.005% by weight, if R S1 is X S —OH, or

(b) from 0.5 to 2% by weight, if R S1 is Y S —(CO)—OH.

20 . The composition according to claim 1 , wherein R S1 is C 1 to C 6 alkane-1,1-diyl.

21 . The composition according to claim 1 , wherein the first selectivity enhancer is of formula S3 or formula S4