[go: up one dir, main page]

US20090215275A1 - Defect Etching of Germanium - Google Patents

Defect Etching of Germanium Download PDF

Info

Publication number
US20090215275A1
US20090215275A1 US12/362,045 US36204509A US2009215275A1 US 20090215275 A1 US20090215275 A1 US 20090215275A1 US 36204509 A US36204509 A US 36204509A US 2009215275 A1 US2009215275 A1 US 2009215275A1
Authority
US
United States
Prior art keywords
etching solution
mol
etching
mno
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/362,045
Other languages
English (en)
Inventor
Laurent Souriau
Valentina Terzieva
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Interuniversitair Microelektronica Centrum vzw IMEC
Original Assignee
Interuniversitair Microelektronica Centrum vzw IMEC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Interuniversitair Microelektronica Centrum vzw IMEC filed Critical Interuniversitair Microelektronica Centrum vzw IMEC
Assigned to INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC) reassignment INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC) ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TERZIEVA, VALENTINA, SOURIAU, LAURENT
Publication of US20090215275A1 publication Critical patent/US20090215275A1/en
Assigned to IMEC reassignment IMEC CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC)
Priority to US13/275,415 priority Critical patent/US8513141B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/32—Polishing; Etching
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K13/00—Etching, surface-brightening or pickling compositions
    • C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
    • C09K13/08—Etching, surface-brightening or pickling compositions containing an inorganic acid containing a fluorine compound
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K13/00—Etching, surface-brightening or pickling compositions
    • C09K13/12—Etching, surface-brightening or pickling compositions containing heavy metal salts in an amount of at least 50% of the non-solvent components

Definitions

  • the present invention relates to defect etching of germanium. More particularly, the present invention relates to an etching solution for revealing defects in a germanium layer, to a method for revealing defects in a germanium layer using such an etching solution and to a method for making such an etching solution.
  • the method and solution according to embodiments of the invention is environmentally and user friendly.
  • Ge can be deposited epitaxially on Si by chemical vapor deposition (CVD).
  • CVD chemical vapor deposition
  • coherent growth is only limited to less than 1 nm.
  • Convenient layers are always thicker and thus present strain relaxation which mainly occurs via the formation of misfit dislocations at the interface between Si and Ge. These misfit dislocations can terminate at the edge of the wafer but often penetrate through the Ge film and end at the surface as a threading dislocation. It is crucial to avoid defects because of their adverse effects on the electrical performance of devices but also on their reliability.
  • defect etching is a simple, fast and low cost technique to assess crystal quality of materials (see M. W Jenkins, J. Electrochem. Soc., Volume 124, Issue 5 (1977), 757-762).
  • etching of semiconductor materials is usually conducted in a three component chemical mixture comprising an oxidizing agent that oxidizes semiconductor surface atoms (e.g. HNO 3 , H 2 O 2 , O 3 , Br 2 , CrO 3 , K 2 Cr 2 O 7 ), a complexing agent that dissolves the oxide that is formed on the surface (e.g. HF) and a solvent for dilution (e.g. H 2 O, CH 3 COOH) (see M. W Jenkins, J. Electrochem. Soc., Volume 124, Issue 5 (1977), 757-762).
  • an oxidizing agent that oxidizes semiconductor surface atoms e.g. HNO 3 , H 2 O 2 , O 3 , Br 2 , CrO 3 , K 2 Cr 2 O 7
  • a complexing agent that dissolves the oxide that is formed on the surface e.g. HF
  • a solvent for dilution e.g. H 2 O, CH 3 COOH
  • the etch rate of these solutions is in the order of a few ⁇ m ⁇ min ⁇ 1 which renders the revelation of defects in thin layers impossible.
  • the etch rate may be decreased but the selectivity towards defects is also drastically decreased.
  • the overall process shifts from a surface reaction controlled regime to a mass controlled regime, or in other words, from a defect preferential etching to a polishing etching which makes it impossible to reveal the defects.
  • the solution exhibits a low etch rate of between 7 and 100 nm ⁇ min ⁇ 1 depending on the doping, strain state and surface orientation of the Ge layer. It has a good selectivity towards defects. With this solution it is possible to reveal dislocations on (100) and (111) oriented Ge.
  • the method and solution according to embodiments of the invention are environmentally and user friendly. They do not make use of carcinogenic substances. Etching solutions according to embodiments of the present invention do not require addition of HF.
  • the method and solution according to embodiments of the invention can advantageously be used for revealing defects in thin III-V semiconductor layers or thin Ge layers, i.e. in III-V semiconductor layers or Ge layers having a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • the present provides an etching solution for revealing defects in a germanium layer.
  • the solution comprises:
  • an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and
  • a solvent such as e.g. water.
  • the etching solution is able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 .
  • the present provides an etching solution for revealing defects in a III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP.
  • the solution comprises:
  • an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and
  • a solvent such as e.g. water.
  • the etching solution is able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 .
  • the etching solution according to embodiments of the invention does not comprise carcinogenic Cr VI . It is furthermore an advantage of the etching solution according to embodiments of the invention that it does not require the use of hydrofluoric acid (HF). Because of the absence of Cr VI and optionally of HF, the etching solution according to embodiments of the present invention is environmentally and user friendly. Because of the low etching rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 the etching solution according to embodiments of the invention may be used for revealing defects in thin germanium layers, i.e. in germanium layers with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • HF hydrofluoric acid
  • the solvent may, for example, be water or another polar protic solvent such as e.g. formic acid, ethanol or methanol.
  • the etch rate may be between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • etch rate the better the etch process can be controlled and the more suitable the etching solution according to embodiments of the invention is when it is to be used for revealing defects, e.g. threading dislocations, in thin Ge layers or thin III-V semiconductor layers, with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • the oxidizing agent may be a component able to, when forming part of an etching solution according to embodiments of the present invention, provide characteristics to the etching solution such that the etching solution:
  • the etching solution may comprise Ce 4+ .
  • Ce 4+ may be present in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 1 mol ⁇ L ⁇ 1 , for example the Ce 4+ -concentration may be lower than 0.4 mol ⁇ L ⁇ 1 .
  • the etching solution may comprise MnO 4 ⁇ .
  • MnO 4 ⁇ may be present in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 0.6 mol ⁇ L ⁇ 1 .
  • the etching solution may furthermore comprise HF.
  • the presence of HF may increase the etch rate but does not change or does not substantially change the selectivity of the etching solution.
  • HF may be present in a concentration of between 0 mol ⁇ L ⁇ 1 and 5 mol ⁇ L ⁇ 1 .
  • the etching solution although comprising quantities of HF according to embodiments of the present invention, may still be more environmentally and user friendly than the prior art methods using HF.
  • An etching solution according to embodiments of the invention may have a selectivity towards the defects of 1.
  • the present invention also provides the use of an etching solution according to embodiments of the invention for revealing defects in a thin germanium layer with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • the present invention also provides the use of an etching solution according to embodiments of the invention for revealing defects in a thin III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP, with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • a thin III-V semiconductor layer e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP
  • the present invention provides a method for making an etching solution for revealing defects in a germanium layer, the etching solution being able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 , or between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • the method comprises:
  • the present invention provides a method for making an etching solution for revealing defects in a III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP, the etching solution being able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 , or between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • the method comprises:
  • Adding a solvent may, for example, be performed by adding water or another polar protic solvent such as e.g. formic acid, ethanol or methanol.
  • providing an oxidizing agent may be performed by providing an oxidizing agent comprising Ce 4+ .
  • Ce 4+ may be provided in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 1 mol ⁇ L ⁇ 1 .
  • providing an oxidizing agent may be performed by providing an oxidizing agent comprising MnO 4 ⁇ .
  • MnO 4 ⁇ may be provided in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 0.6 mol ⁇ L ⁇ 1 .
  • the method may furthermore comprise adding HF to the etching solution.
  • Adding HF may increase the etch rate of the etching solution but does not or not substantially change the selectivity of the etching solution.
  • HF may be provided in a concentration of between 0 mol ⁇ L ⁇ 1 and 5 mol ⁇ L ⁇ 1 .
  • the present invention also provides an etching solution for revealing defects in a germanium layer, the etching solution being made by a method according to embodiments of the invention.
  • the present invention also provides an etching solution for revealing defects in a III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP, the etching solution being made by a method according to embodiments of the invention.
  • the present invention provides a method for revealing defects in a germanium layer.
  • the method comprises immersing a substrate comprising the germanium layer in an etching solution comprising an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and a solvent, the etching solution being able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • the present invention provides a method for revealing defects in a III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP.
  • the method comprises immersing a substrate comprising the III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g.
  • the etching solution comprising an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and a solvent, the etching solution being able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • Immersing the substrate comprising the Ge layer or the III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP, in the etching solution may be performed during a time period of between 1.5 minutes and 10 minutes, depending on the concentration of oxidizing agent present in the etching solution.
  • FIG. 1 illustrates SEM images of a 1.5 ⁇ m Ge layer on Si(100) after etching in (a) a Ce 4+ /H 2 O solution according to embodiments of the present invention comprising 0.1 mol ⁇ L ⁇ 1 for 10 minutes and (b) a Ce 4+ /H 2 O solution according to embodiments of the present invention comprising 1 mol ⁇ L ⁇ 1 for 1.5 minutes.
  • FIG. 2 shows Atomic Force Microscopy (AFM) images (left part) and their respective tip trace through the etch figure (pit or hillock) after etching of a 1.5 ⁇ m thick Ge layer on Si(100) in a Ce 4+ /H 2 O solution according to embodiments of the present invention comprising 0.1 mol ⁇ L ⁇ 1 (upper part) and after etching of a 1.5 ⁇ m thick Ge layer on Si(100) in a Ce 4+ /H 2 O solution according to embodiments of the present invention comprising 0.6 mol ⁇ L ⁇ 1 (lower part).
  • AFM Atomic Force Microscopy
  • FIG. 3 shows the threading dislocation density for a 1.5 ⁇ m thick Ge layer after etching in Ce 4+ /H 2 O solutions according to embodiments of the present invention with different Ce 4+ -concentrations.
  • FIG. 4 shows the etch rate for a 1.5 ⁇ m thick Ge layer on Si(100) after etching in a Ce 4+ /H 2 O solution according to embodiments of the present invention as a function of Ce 4+ -concentration.
  • FIG. 5 shows SEM (left) and AFM (right) pictures of a 1.5 ⁇ m thick Ge layer on Si(100) after etching in a MnO 4 ⁇ /HF/H 2 O solution according to embodiments of the invention.
  • FIG. 6 shows the threading dislocation density for a 1.5 ⁇ m thick Ge layer after etching in a MnO 4 ⁇ /HF/H 2 O solution according to embodiments of the present invention with a MnO 4 ⁇ -concentration of 0.01 mol ⁇ L ⁇ 1 and for different HF-concentrations.
  • FIG. 7 shows etch depth as a function of etching time and as a function of HF-concentration for a 1.5 ⁇ m thick Ge layer after etching in a MnO 4 ⁇ /HF/H 2 O solution according to embodiments of the invention.
  • FIG. 8 shows the threading dislocation density for a 1.5 ⁇ m thick Ge layer after etching in different etching solutions according to embodiments of the invention.
  • the present invention provides an etching solution for revealing defects in a germanium layer, a method for revealing defects in a germanium layer using such an etching solution and a method for making such an etching solution.
  • the etching solution comprises:
  • an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and
  • the etching solution being able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 .
  • the solvent may, for example, be water or another polar protic solvent such as for example a carboxylic acid (e.g. formic acid or acetic acid).
  • a carboxylic acid e.g. formic acid or acetic acid
  • the solvent should not be too reactive when mixed with the oxidizing agent.
  • Carboxylic acids are already in an oxidized form so that they are less reactive with the oxidizing agent than, for example, alcohols such as ethanol or methanol which, when mixed with a strong oxidising agent, will oxidize to form their carbonyl counterpart.
  • the etch rate may be between 4 nm ⁇ min ⁇ 1 and 200 nm ⁇ min ⁇ 1 , or between 4 nm ⁇ min ⁇ 1 and 100 nm ⁇ min ⁇ 1 .
  • the etching solution according to embodiments of the invention does not comprise carcinogenic Cr VI or other carcinogenic substances, as is the case for prior art solutions. Furthermore the etching solution according to embodiments of the invention does not require the use of hydrofluoric acid (HF). Because of the absence of Cr VI and optionally of HF, the etching solution according to embodiments of the present invention is environmentally and user friendly. In other embodiments, the etching solution does comprise some HF, but less than prior art solutions, thus being more environmentally and user friendly than these prior art solutions.
  • HF hydrofluoric acid
  • the etching solution according to embodiments of the invention may be used for revealing defects in thin germanium layers, i.e. in germanium layers with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • the oxidizing agent may be a component able to, when part of an etching solution according to embodiments of the present invention:
  • the etching solution may comprise Ce 4+ as an oxidizing agent and water as a solvent.
  • the etching solution according to this first embodiment may be referred to as a Ce 4+ /H 2 O solution.
  • a source for Ce 4+ for example cerium ammonium nitrate ((NH 4 ) 2 Ce(NO 3 ) 6 ) may be used because it has a high solubility of 141 g/100 ml in water at 25° C.
  • Ce 4+ -sources can be used, such as e.g.
  • the etching solution according to the first embodiment may comprise Ce 4+ in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 3 mol ⁇ L ⁇ 1 , for example between 0.01 mol ⁇ L ⁇ 1 and 1 mol ⁇ L ⁇ 1 or between 0.01 mol ⁇ L ⁇ 1 and 0.4 mol ⁇ L ⁇ 1 . It has to be noted that the etch rate of the solution increases with increasing concentration of Ce 4+ . Hence, a suitable Ce 4+ concentration may be chosen as a function of the desired etch rate.
  • etching solution according to the first embodiment will further be described by means of some experiments.
  • different amounts of (NH 4 ) 2 Ce(NO 3 ) 6 were dissolved in H 2 O so as to obtain different etching solutions with different Ce 4+ -concentration.
  • Etching was carried out at a 1.5 ⁇ m thick Ge layer on Si(100) and was performed by dipping 2 ⁇ 2 cm 2 samples in a beaker containing the etching solution.
  • the solutions were always freshly prepared, unless otherwise mentioned.
  • the samples were partially immersed in the etching solution so as to produce a step which was used for the determination of the etch rate (ER). No stirring was applied to the solutions during etching and all experiments were done at room temperature.
  • the defect etching capability of the Ce 4+ /H 2 O solution according to the first embodiment was examined for Ce 4+ -concentrations ranging from 0.01 mol ⁇ L ⁇ 1 to 1 mol ⁇ L ⁇ 1 .
  • Typical examples of SEM and AFM images of the Ge surface after etching are respectively illustrated in FIG. 1 and FIG. 2 , thereby illustrating the advantages of the Ce 4+ /H 2 O solution according to the first embodiment to reveal defects, e.g. threading dislocations, in germanium.
  • FIG. 1 shows a SEM picture of the 1.5 ⁇ m thick Ge layer on Si(100) after etching in Ce 4+ /H 2 O solutions with different Ce 4+ -concentrations and for different times.
  • FIG. 1( a ) shows a Ge layer after etching for 10 minutes in a Ce 4+ /H 2 O solution comprising 0.1 mol ⁇ L ⁇ 1 Ce 4+ .
  • FIG. 1( b ) shows a Ge layer after etching for 1.5 minutes in a Ce 4+ /H 2 O solution comprising 1 mol ⁇ L ⁇ 1 Ce 4+ . It has been found that, depending on the concentration of Ce 4+ ions in the solution, the morphology of the Ge surface after etching is different. Etch pits are observed for a Ce 4+ -concentration lower than 0.4 mol ⁇ L ⁇ 1 while hillocks are observed for Ce 4+ -concentration of 0.4 mol ⁇ L ⁇ 1 and higher.
  • FIG. 2 shows an AFM picture of the Ge layer after etching in a Ce 4+ /H 2 O solution comprising 0.1 mol ⁇ L ⁇ 1 Ce 4+ (see upper part of FIG. 2 ) and in a Ce 4+ /H 2 O solution comprising 0.6 mol ⁇ L ⁇ 1 Ce 4+ (see lower part of FIG. 2 ) together with their respective tip trace through the AFM figure along the line AA′.
  • the threading dislocation density has been determined for different Ce 4+ -concentrations between 0.01 mol ⁇ L ⁇ 1 and 1 mol ⁇ L ⁇ 1 (see FIG. 3 ).
  • Etching time has been adapted for the different concentrations in order to prevent removal of the entire Ge layer. Therefore, the Ge layer was etched for 10 min in Ce 4+ /H 2 O solutions comprising between 0.01 mol ⁇ L ⁇ 1 and 0.3 mol ⁇ L ⁇ 1 , for 3 min in Ce 4+ /H 2 O solutions comprising between 0.4 mol ⁇ L ⁇ 1 and 0.75 mol ⁇ L ⁇ 1 and for 1.5 min in Ce 4+ /H 2 O solutions comprising 1 mol ⁇ L ⁇ 1 . From FIG. 3 it can be seen that for all Ce 4+ -concentrations between 0.01 mol ⁇ L ⁇ 1 and 1 mol ⁇ L ⁇ 1 approximately a same defect density of 10 8 /cm 2 was obtained.
  • the dashed line indicated with arrow 5 in FIG. 3 indicates a TDD of 8.10 7 /cm 2 obtained with a prior art CrO 3 /HF/H 2 O solution.
  • TDD obtained with the Ce 4+ /H 2 O solution according to the first embodiments of the present invention agrees well within experimental errors (indicated by I in FIG. 3 ) with the value determined by defect etching with the prior art CrO 3 /HF/H 2 O solution or by cross-section TEM.
  • the etching solution according to the first embodiments of the invention does not comprise carcinogenic Cr VI nor HF, it leads to comparable results as the prior art solution comprising Cr VI as well as HF.
  • etching rate e.g. a relatively low etching rate (ER).
  • the ER obtained for Ge layers in the Ce 4+ /H 2 O solution according to the first embodiment of the invention shows a linear behaviour as a function of the Ce 4+ -concentration (see FIG. 4 ). This indicates that the rate limiting step in the etching reaction is the oxidation of Ge surface atoms which is typical for etching with a preferential behaviour (e.g. anisotropic etching, defect etching). Moreover this shows that the oxidation kinetics of Ge atoms by Ce 4+ ions is of first order.
  • the Ce 4+ -concentration may be lower than 0.4 mol ⁇ L ⁇ 1 in order to have good control on the etch depth.
  • Good control on the etch depth may, according to these embodiments, be obtained because in these cases the ER is lower than 200 nm ⁇ min ⁇ 1 .
  • the ER may be between 4 and about 100 nm ⁇ min ⁇ 1 .
  • a particularly useful range of etch rates for such really thin Ge layers is indicated by the region beneath the dashed line in FIG. 4 .
  • the Ce 4+ /H 2 O solution may comprise a Ce 4+ -concentration of between 0.01 mol ⁇ L ⁇ 1 and 0.3 mol ⁇ L ⁇ 1 . It is worth noting that, as can be seen from FIG. 4 , for a Ce 4+ -concentration of 0.01 mol ⁇ L ⁇ 1 , an ER of only 4 nm ⁇ min ⁇ 1 may be obtained.
  • the selectivity S towards defects, e.g. threading dislocations, of a solution may be assessed by looking at the ratio of the lateral size of the etched figures (i.e. etch pits or hillocks) and the etch depth:
  • the selectivity S of the Ce 4+ /H 2 O solution towards defects, e.g. threading dislocations, is independent of the Ce 4+ -concentration and was determined to be approximately 1.
  • the Ce 4+ /H 2 O solution according to the first embodiment of the invention is liable to aging.
  • the Ce 4+ /H 2 O solution according to the first embodiment of the invention is unstable in time. Because of this aging the selectivity of the Ce 4+ /H 2 O solution may be reduced as a function of time. Therefore, it is advantageous, to obtain good results, to always use freshly prepared Ce 4+ /H 2 O solutions.
  • the etching solution may comprise MnO 4 ⁇ as an oxidizing agent and water as a solvent.
  • the etching solution according to this second embodiment may be referred to as a MnO 4 ⁇ /H 2 O solution.
  • a source for MnO 4 ⁇ for example potassium permanganate (KMnO 4 ) may be used.
  • MnO 4 ⁇ potassium permanganate
  • Magnesium permanganate, Sodium permanganate, Cesium permanganate may also be used as MnO 4 -sources.
  • the etching solution according to the second embodiment of the invention may comprise MnO 4 ⁇ in a concentration of between 0.01 mol ⁇ L ⁇ 1 and 0.6 mol ⁇ L ⁇ 1 .
  • the MnO 4 ⁇ /H 2 O solution may comprise HF.
  • HF may be present in the MnO 4 ⁇ /H 2 O solution in a concentration of between 0 mol ⁇ L ⁇ 1 and 5 mol ⁇ L ⁇ 1 . Because of this low concentration of HF present, the MnO 4 ⁇ /H 2 O solution may still be environmentally and user friendly. According to other embodiments, although in these cases less environmentally and user friendly and not really contributing to improvement of the etching solution, the MnO 4 ⁇ /H 2 O solution may also comprise higher concentrations of HF. The presence of HF may increase the ER of the etching solution.
  • etching solution according to the second embodiment will further be described by means of some experiments.
  • different amounts of KMnO 4 were dissolved in H 2 O so as to obtain different etching solutions with different MnO 4 ⁇ -concentrations.
  • HF was added in different concentrations.
  • etching was carried out at a 1.5 ⁇ m thick Ge layer on Si(100) and was performed by dipping 2 ⁇ 2 cm 2 samples in a beaker containing the etching solution. The solutions were always freshly prepared, unless otherwise mentioned. The samples were partially immersed in the etching solution so as to produce a step which was used for the determination of the ER.
  • MnO 4 ⁇ /H 2 O solution with or without HF were evaluated with respect to their ability for revealing defects, e.g. threading dislocations in the Ge layers.
  • the MnO 4 ⁇ -concentration in the MnO 4 ⁇ /H 2 O solutions used ranged from 0.01 mol ⁇ L ⁇ 1 to 0.6 mol ⁇ L ⁇ 1 . All solutions allowed revelation of the defects, e.g. threading dislocations but the best results were obtained with low concentration of MnO 4 ⁇ , i.e. concentrations of MnO 4 ⁇ in the order of 0.01 mol ⁇ L ⁇ 1 .
  • the determined TDD of approximately 10 8 /cm 2 appears to be substantially independent of the HF concentration present in the solution and is in accordance with the results obtained with defect etching techniques using a prior art CrO 3 /HF/H 2 O solution (see dashed line indicated with reference number 5 in FIG. 6 ) but also with TEM characterization.
  • FIG. 7 illustrates removal depth as a function of etching time for these solutions.
  • Curve 6 shows the ER for a solution comprising no HF
  • curve 7 shows the ER for a solution comprising 5 mol ⁇ L ⁇ 1 HF
  • curve 8 shows the ER for a solution comprising 12.5 mol ⁇ L ⁇ 1 HF. From FIG.
  • an ER of between 18 nm ⁇ min ⁇ 1 and 20 nm ⁇ min ⁇ 1 can be derived for solutions comprising 0 mol ⁇ L ⁇ 1 HF and 12.5 HF and an ER of 35 nm ⁇ min ⁇ 1 can be derived for solutions comprising 5 mol ⁇ L ⁇ 1 HF. From this it is clear that addition of HF increases the ER. However, when the concentration of HF becomes too high, the ER is decreased again.
  • HF may be more efficient in the dissolution of GeO 2 oxide but also the increase of the acidity of the solution drastically increases the oxidation potential of MnO 4 ⁇ anions.
  • the higher ER obtained with 5 mol ⁇ L ⁇ 1 HF than for 12.5 mol ⁇ L ⁇ 1 there is no obvious explanation for the higher ER obtained with 5 mol ⁇ L ⁇ 1 HF than for 12.5 mol ⁇ L ⁇ 1 .
  • an ER between 20 and 50 nm ⁇ min ⁇ 1 may be obtained depending the HF concentration.
  • the low ER makes the etching solutions according to the second embodiments suitable to be used for easily revealing defects, e.g. threading dislocations in thin Ge layers with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • the selectivity S towards defects e.g. threading dislocations of the MnO 4 ⁇ /H 2 O and MnO 4 ⁇ /HF/H 2 O solutions with a MnO 4 ⁇ concentration of 0.01 mol ⁇ L ⁇ 1 is approximately 1 independent of the HF concentration, which is comparable to the results obtained for the etching solution according to the first embodiments of the invention.
  • FIG. 8 illustrates the defect density for etching solutions according to embodiments of the present invention which exhibit a low ER and which may thus be suitable for revealing defects, e.g. threading dislocations in thin Ge layers with a thickness of between 20 nm and 10 ⁇ m, for example between 20 nm and 2 ⁇ m, between 20 nm and 1 ⁇ m or between 20 nm and 200 nm.
  • a first example is a Ce 4+ /H 2 O solution with a Ce 4+ -concentration of 0.01 mol ⁇ L ⁇ 1 . With this solution an ER of 3.5 nm ⁇ min ⁇ 1 was obtained.
  • defects e.g. threading dislocations
  • a second example is a Ce 4+ /H 2 O solution with a Ce 4+ -concentration of 0.1 mol ⁇ L ⁇ 1 . With this solution an ER of 40 nm ⁇ min ⁇ 1 was obtained.
  • defects, e.g. threading dislocations are revealed with defect density of more than 10 8 /cm 2 (see curve indicated with reference number 11 ).
  • a third example is a MnO 4 ⁇ /HF/H 2 O comprising 0.01 mol ⁇ L ⁇ 1 MnO 4 ⁇ , 10 ml HF and 40 ml H 2 O. With this solution an ER of 50 nm ⁇ min ⁇ 1 was obtained. After etching for 2 minutes, defects, e.g. threading dislocations, are revealed with defect density of more than 10 8 /cm 2 (see curve indicated with reference number 12 ).
  • a fourth example is a MnO 4 ⁇ /HF/H 2 O comprising 0.01 mol ⁇ L ⁇ 1 MnO 4 ⁇ , 25 ml HF and 25 ml H 2 O. With this solution an ER of 20 nm ⁇ min ⁇ 1 was obtained. After etching for 2 minutes, defects, e.g. threading dislocations, are revealed with defect density of more than 10 8 /cm 2 (see curve indicated with reference number 13 ).
  • the etching solution may also be for revealing defects in a III-V semiconductor layer, e.g. a layer comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP.
  • the present invention provides an etching solution for revealing defects a III-V semiconductor layer, e.g. GaAs or InP layer, the solution comprising:
  • an oxidizing agent comprising Ce 4+ or MnO 4 ⁇ , and
  • a solvent such as e.g. water.
  • the etching solution is able to exhibit an etch rate of between 4 nm ⁇ min ⁇ 1 and 450 nm ⁇ min ⁇ 1 .
  • III-V semiconductor layers e.g. layers comprising GaAs or InP or a combination thereof such as e.g. GaInAs or GaInP, with the etching solution according to embodiments of the invention as was described above in case of Ge layers.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Weting (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)
  • ing And Chemical Polishing (AREA)
US12/362,045 2008-01-31 2009-01-29 Defect Etching of Germanium Abandoned US20090215275A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/275,415 US8513141B2 (en) 2008-01-31 2011-10-18 Defect etching of germanium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP08150895.4 2008-01-31
EP20080150895 EP2090675B1 (de) 2008-01-31 2008-01-31 Fehlerätzen von Germanium

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US13/275,415 Division US8513141B2 (en) 2008-01-31 2011-10-18 Defect etching of germanium

Publications (1)

Publication Number Publication Date
US20090215275A1 true US20090215275A1 (en) 2009-08-27

Family

ID=39540694

Family Applications (2)

Application Number Title Priority Date Filing Date
US12/362,045 Abandoned US20090215275A1 (en) 2008-01-31 2009-01-29 Defect Etching of Germanium
US13/275,415 Expired - Fee Related US8513141B2 (en) 2008-01-31 2011-10-18 Defect etching of germanium

Family Applications After (1)

Application Number Title Priority Date Filing Date
US13/275,415 Expired - Fee Related US8513141B2 (en) 2008-01-31 2011-10-18 Defect etching of germanium

Country Status (3)

Country Link
US (2) US20090215275A1 (de)
EP (1) EP2090675B1 (de)
JP (1) JP5552238B2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150227650A1 (en) * 2013-07-19 2015-08-13 Tsinghua University Method for modeling etching yield and etching surface evolution simulation method
CN114316990A (zh) * 2021-12-09 2022-04-12 湖北兴福电子材料有限公司 一种高蚀刻锥角的锗蚀刻液

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3576631A (en) * 1967-02-24 1971-04-27 Itek Corp Physical development composition and process of using same
US4294651A (en) * 1979-05-18 1981-10-13 Fujitsu Limited Method of surface-treating semiconductor substrate
US4971654A (en) * 1987-08-27 1990-11-20 Wacker-Chemitronic Gesellschaft Fur Electronik-Grundstoffe Mbh Process and apparatus for etching semiconductor surfaces
US20020142619A1 (en) * 2001-03-30 2002-10-03 Memc Electronic Materials, Inc. Solution composition and process for etching silicon
US20050169096A1 (en) * 2003-07-01 2005-08-04 Lee Hyo-San PAA- based etchant, methods of using same, and resultant structures
US20060032836A1 (en) * 2001-11-16 2006-02-16 Ferro Corporation Methods of controlling the properties of abrasive particles for use in chemical-mechanical polishing slurries
US20060144823A1 (en) * 2004-12-30 2006-07-06 Kim Young-Hun Etching solution for D-defect evaluation in silicon wafer and evaluation method using the same

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1068840B (de) * 1959-11-12 Gottlob Epple Mineralölwerk, Stuttgart - Bad Cannstatt Mittel zum Entfernen von silberhaltigen Rückständen von Kunststoffteil'en
JPS49105448A (de) * 1973-02-07 1974-10-05
DE3583583D1 (de) * 1984-11-17 1991-08-29 Daikin Ind Ltd Aetzzusammensetzung.
JPH08139416A (ja) * 1994-11-14 1996-05-31 Sony Corp 化合物半導体層の臨界膜厚の求め方およびそれを用いた光半導体装置の製造方法
JP3201251B2 (ja) * 1996-03-18 2001-08-20 松下電器産業株式会社 誘電体素子の製造方法
JPH111781A (ja) 1997-06-06 1999-01-06 Advanced Display:Kk エッチング液管理方法及び装置
JPH1167742A (ja) * 1997-08-25 1999-03-09 Sumitomo Metal Ind Ltd 半導体基板用エッチング液およびエッチング方法
US6600557B1 (en) * 1999-05-21 2003-07-29 Memc Electronic Materials, Inc. Method for the detection of processing-induced defects in a silicon wafer
CA2310155C (en) * 1999-06-01 2007-05-29 Jennifer Bardwell A process for etching gallium nitride compound based semiconductors
JP4510979B2 (ja) * 2000-02-23 2010-07-28 ルネサスエレクトロニクス株式会社 ルテニウム又は酸化ルテニウム除去液の使用方法、及びルテニウム又は酸化ルテニウムの除去方法
KR100357981B1 (ko) * 2000-06-29 2002-10-25 삼성전자 주식회사 회절격자 제조장치 및 그 제조방법
KR100390553B1 (ko) * 2000-12-30 2003-07-07 주식회사 동진쎄미켐 근적외선 분광기를 이용한 금속막 에칭 공정 제어방법 및에쳔트 조성물의 재생방법
CA2408483C (en) * 2002-10-17 2011-01-04 Yujie Han Laser chemical fabrication of nanostructures
GB0313402D0 (en) * 2003-06-11 2003-07-16 Shin Etsu Handotai Europ Ltd Semiconductor defect etch
CN100546006C (zh) * 2003-09-09 2009-09-30 Csg索拉尔有限公司 蚀刻硅的改进方法
JP2008115310A (ja) * 2006-11-07 2008-05-22 Tsurumi Soda Co Ltd 導電性高分子用エッチング液及び導電性高分子をパターニングする方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3576631A (en) * 1967-02-24 1971-04-27 Itek Corp Physical development composition and process of using same
US4294651A (en) * 1979-05-18 1981-10-13 Fujitsu Limited Method of surface-treating semiconductor substrate
US4971654A (en) * 1987-08-27 1990-11-20 Wacker-Chemitronic Gesellschaft Fur Electronik-Grundstoffe Mbh Process and apparatus for etching semiconductor surfaces
US20020142619A1 (en) * 2001-03-30 2002-10-03 Memc Electronic Materials, Inc. Solution composition and process for etching silicon
US20060032836A1 (en) * 2001-11-16 2006-02-16 Ferro Corporation Methods of controlling the properties of abrasive particles for use in chemical-mechanical polishing slurries
US20050169096A1 (en) * 2003-07-01 2005-08-04 Lee Hyo-San PAA- based etchant, methods of using same, and resultant structures
US20060144823A1 (en) * 2004-12-30 2006-07-06 Kim Young-Hun Etching solution for D-defect evaluation in silicon wafer and evaluation method using the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150227650A1 (en) * 2013-07-19 2015-08-13 Tsinghua University Method for modeling etching yield and etching surface evolution simulation method
CN114316990A (zh) * 2021-12-09 2022-04-12 湖北兴福电子材料有限公司 一种高蚀刻锥角的锗蚀刻液

Also Published As

Publication number Publication date
EP2090675B1 (de) 2015-05-20
US8513141B2 (en) 2013-08-20
JP5552238B2 (ja) 2014-07-16
JP2009182331A (ja) 2009-08-13
EP2090675A1 (de) 2009-08-19
US20120034787A1 (en) 2012-02-09

Similar Documents

Publication Publication Date Title
US5705089A (en) Cleaning fluid for semiconductor substrate
KR100930294B1 (ko) Ｓｉ－기판 및 ＳｉＧｅ－기판을 위한 크롬이 없는 식각용액, 상기 식각 용액을 이용하여 결함을 나타내기위한방법 및 상기 식각 용액을 이용하여 Ｓｉ－기판 및ＳｉＧｅ－기판을 처리하기 위한 프로세스
CN102007394B (zh) 特别用于应变或应力硅材料的刻蚀组合物、表征这种材料表面上的缺陷的方法，和用刻蚀组合物处理这种表面的工艺
US6239039B1 (en) Semiconductor wafers processing method and semiconductor wafers produced by the same
JPS62106631A (ja) 選択性エツチング剤
US8513141B2 (en) Defect etching of germanium
EP1734572B1 (de) Verfahren zur bewertung von kristalldefekten eines siliziumwafers
JPH11502975A (ja) エピタキシャル層に関する半導体基板の優先的エッチング
US11959191B2 (en) Method for manufacturing silicon single crystal wafer and silicon single crystal wafer
Douani et al. Formation of aligned silicon-nanowire on silicon in aqueous HF/(AgNO3+ Na2S2O8) solution
RU2542894C1 (ru) Состав полирующего травителя для теллурида кадмия-ртути
JP3629694B2 (ja) シリコンウェーハの評価方法
TW201413784A (zh) 鍺層表面平坦化方法以及半導體結構及其製造方法
JP7811689B1 (ja) エッチング液組成物
KR102890398B1 (ko) 실리콘 및 실리콘 저마늄 식각액 조성물, 및 이를 이용한 패턴 형성 방법
Possner et al. Organic Peracid Etches: a new class of chromium free etch solutions for the delineation of defects in different semiconducting materials
Maehliss et al. A Chromium-free Defect Etching Solution for Application on SOI
JP4838578B2 (ja) 微細加工処理剤、及びそれを用いた微細加工処理方法
Uno et al. Formation of a step/terrace structure of Si (111) on SiO2 by wet chemical treatment
JP2006267048A (ja) 断面観察用試料の作製方法
CN119614204A (zh) 一种用于石英晶片减薄的缓冲氧化蚀刻液
Peddeti Chemical Mechanical Polishing of Germanium and Indium Phosphide for Microelectronic Applications
JP2006179513A (ja) 微細加工処理剤、及びそれを用いた微細加工処理方法
Górska et al. HBV deep mesa etching in InGaAs/InAlAs/AlAs heterostructures on InP substrate
Sax et al. Polysilicon overfill etch back using wet chemical spin-process technology. An alternative to traditional dry etch and CMP technigues

Legal Events

Date Code Title Description
AS Assignment

Owner name: INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC),

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SOURIAU, LAURENT;TERZIEVA, VALENTINA;REEL/FRAME:022663/0925;SIGNING DATES FROM 20090323 TO 20090327

AS Assignment

Owner name: IMEC, BELGIUM

Free format text: CHANGE OF NAME;ASSIGNOR:INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC);REEL/FRAME:023594/0846

Effective date: 19840116

Owner name: IMEC,BELGIUM

Free format text: CHANGE OF NAME;ASSIGNOR:INTERUNIVERSITAIR MICROELEKTRONICA CENTRUM (IMEC);REEL/FRAME:023594/0846

Effective date: 19840116

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION