1. A hinge joint (J) for use in a three point pressure system of a knee brace comprising a first part (4) that is connectable to a femoral arm (F) of a knee brace and a second part (3) that is telescopically mounted to the first part,
characterized in that the telescopic mounting of the second part (3) to the first part (4) is constructed in a manner that enables second part (3) to telescope out of the first part (4) as the leg is extended and to telescope back into the first part (4) as the leg flexes so as to dynamically change the pressure applied to the lateral side of the knee condyle with changes in the angulation of the leg.
2. The hinge joint according to claim 1, wherein each of the first (4) and second (3) parts have ramps (3A, 4A), the ramps (3A) of the second part riding over the ramps (4A) of the first part during flexion and extension.
3. A knee brace having three point pressure system, comprising:
a femoral arm (F),
a tibial arm (T), and
a hinge joint (J) connecting the femoral arm (F) with the tibial arm (T),
wherein the hinge joint (J) comprises a first part (4) that is connected to the femoral arm (F) and a second part (3) that is that is telescopically mounted to the first part (4),
characterized in that the telescopic mounting of the second part (3) to the first part (4) is constructed in a manner that enables second part (3) to telescope out of the first part (4) as the leg is extended and to telescope back into the first part (4) as the leg flexes so as to dynamically change the pressure applied to the lateral side of the knee condyle with changes in the angulation of the leg.
4. The knee brace according to claim 3, wherein each of the first (4) and second (3) parts have ramps (3A, 4A), the ramps of the second part (3A) riding over the ramps of the first part (4A) during flexion and extension.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for fabricating a semiconductor device, comprising the steps of:
providing a substrate containing a first layer comprising GaAs and a second layer comprising InGaP, wherein the first and second layers are joined across a common interface comprising InGaAsP;
etching the first layer with a first liquid composition until at least a portion of the interface is exposed; and
etching the interface with a second composition that exhibits etch stop behavior with respect to InGaP, the second composition comprising an oxidizing agent disposed in a liquid medium.
2. The method of claim 1, wherein the semiconductor device is a field effect transistor.
3. The method of claim 1, wherein the semiconductor device is a heterojunction bipolar transistor.
4. The method of claim 1, wherein the second composition is as aqueous solution comprising HCl and H2O2.
5. The method of claim 4, wherein the second composition is a dilute aqueous solution.
6. The method of claim 4, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:20 to about 5:4.
7. The method of claim 4, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:12 to about 3:4.
8. The method of claim 4, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:12 to about 1:4.
9. The method of claim 1, wherein the InGaAsP has the formula InxGa1xAsyP1y, wherein 0<x, y<1.
10. The method of claim 1, wherein the InGaP has the formula InxGa(1x)P, where 0<x<1.
11. The method of claim 1, wherein the liquid medium is water.
12. The method of claim 1, wherein the first composition exhibits etch stop behavior with respect to InGaP.
13. The method of claim 1, wherein the first and second layers are epitaxial layers.
14. The method of claim 1, wherein the substrate has a plurality of interfaces comprising InGaAsP.
15. The method of claim 14, wherein each of the plurality of interfaces is bounded on a first side by a layer comprising GaAs and is bounded on a second side by a layer comprising InGaP.
16. The method of claim 1, wherein the first and second layers are essentially parallel.
17. The method of claim 1, further comprising the step of etching the second layer with a third liquid composition.
18. The method of claim 17, wherein the third composition comprises a mixture of H3PO4 and HCl.
19. A method for fabricating a semiconductor device, comprising:
providing a Group III-V compound heterostructure which includes contiguous first and second epitaxial layers having diverse compositions, said first and second layers comprising, respectively, GaAs and InGaP and having disposed between them an interface comprising InGaAsP;
subjecting the heterostructure to a first etchant that selectively etches the first layer; and
subjecting the heterostructure to a second etchant that selectively etches the interface, the second etchant comprising an aqueous solution of H2O2 having a pH of less than 7.
20. The method of claim 19, wherein the pH of the second etchant is greater than about 5.
21. The method of claim 19, wherein the second etchant further comprises HCl.
22. The method of claim 21, wherein the mole ratio of H2O2 to HCl in the second etchant is within the range of about 1:20 to about 5:4.
23. The method of claim 21, wherein the mole ratio of H2O2 to HCl in the second etchant is within the range of about 1:12 to about 3:4.
24. A method for etching a substrate, comprising the steps of:
providing a substrate comprising formations of InxGa1xAsyP1y, wherein 0<x, y<1; and
etching the formations with a composition comprising a dilute aqueous solution of H2O2 and HCl.
25. The method of claim 24, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:20 to about 5:4.
26. The method of claim 24, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:12 to about 3:4.
27. The method of claim 24, wherein the mole ratio of H2O2 to HCl in the solution is within the range of about 1:12 to about 1:4.
28. The method of claim 25, wherein the concentration of HCl in the solution is less than about 0.5M.
29. A method for fabricating a field effect transistor, comprising the steps of:
providing a substrate comprising a plurality of epitaxial layers containing a first layer of GaAs and a second layer of InGaP, said first and second layer having a common interface comprising InGaAsP; and
etching the interface with a composition comprising an oxidizing agent disposed in a liquid medium.
30. The method of claim 29, wherein the oxidizing agent is a peroxide.
31. The method of claim 30, wherein the peroxide is H2O2.
32. The method of claim 29, wherein the liquid medium is water.
33. The method of claim 29, wherein the composition comprises H2O2, HCl and H2O.
34. The method of claim 33, wherein the concentration of HCl in the liquid medium is less than about 0.5M.
35. The method of claim 33, wherein the concentration of HCl in the liquid medium is within the range of about 0.2M to about 0.5M.