Method of growing a single crystal diamond
Synthetic monocrystalline diamond compositions having one or more monocrystalline diamond layers formed by chemical vapor deposition, the layers including one or more layers having an increased concentration of one or more impurities (such as boron and/or isotopes of carbon), as compared to other layers or comparable layers without such impurities. Such compositions provide an improved combination of properties, including color, strength, velocity of sound, electrical conductivity, and control of defects. A related method for preparing such a composition is also described., as well as a system for use in performing such a method, and articles incorporating such a composition.
1 . A method of growing single crystal diamond, the method comprising:
polishing a CVD grown single crystal seed having a (100) orientation;
placing the seed in a substrate holder in a microwave plasma reactor;
evacuating the reactor to a pressure of less than 10 millitorr;
backfilling the reactor with hydrogen having a purity of at least approximately 99.999%;
providing microwave power to create a plasma ball;
heating the substrate holder to approximately 900° C.;
adding methane containing diborane to obtain a mixture of methane and hydrogen containing approximately 1000 ppm diobrane;
converting part of the hydrogen to atomic hydrogen;
after formation of a desired thickness of single crystal boron doped diamond, terminating the flow of diborane;
continuing the flow of methane for a predetermined time after termination of the diborane;
after the end of flow of the methane, terminating the microwave power; and
cooling the substrate holder to room temperature.
2 . The method of claim 1 wherein the desired thickness of the single crystal boron doped diamond is at least approximately 250 micrometers.
3 . The method of claim 1 wherein the single crystal boron doped diamond has a (100) crystal orientation.
4 . The method of claim 1 wherein the growth rate of diamond is approximately 1 micrometer per hour.
5 . The method of claim 1 and further comprising cleaning the single crystal boron doped diamond in a mixture of chromic acid and sulfuric acid at a temperature of approximately 250° C.
6 . The method of claim 1 wherein the predetermined time is approximately 75 hours.
7 . The method of claim 1 wherein hydrogen is backfilled to approximately 40 Torr at a rate of approximately 100 sccm.
8 . The method of claim 1 wherein the mixture of methane and hydrogen comprises approximately 1% methane.
9 . A method of growing single crystal diamond, the method comprising:
polishing a single crystal seed having a (100) orientation;
placing the seed in a substrate holder in a microwave plasma reactor;
filling the reactor with hydrogen having a purity of at least approximately 99.999%;
providing microwave power to create a plasma ball;
heating the substrate holder to approximately 900° C.;
adding methane containing diborane;
after formation of a desired thickness of single crystal boron doped diamond, terminating the flow of diborane;
continuing the flow of methane for a predetermined time after termination of the diborane;
after the end of flow of the methane, terminating the microwave power; and
cooling the substrate holder to room temperature.
10 . The method of claim 9 wherein the desired thickness of the single crystal boron doped diamond is at least approximately 250 micrometers.
11 . The method of claim 9 wherein the single crystal boron doped diamond has a (100) crystal orientation.
12 . The method of claim 9 wherein the growth rate of diamond is approximately 1 micrometer per hour.
13 . The method of claim 9 and further comprising cleaning the single crystal boron doped diamond in a mixture of chromic acid and sulfuric acid at a temperature of approximately 250° C.
14 . The method of claim 9 wherein the predetermined time is approximately 75 hours.
15 . A method of growing single crystal diamond, the method comprising:
placing a polished seed in a substrate holder in a microwave plasma reactor;
filling the reactor with hydrogen;
providing microwave power to create a plasma ball;
heating the substrate holder to approximately 900° C.;
adding methane containing diborane;
after formation of a desired thickness of single crystal boron doped diamond, terminating the flow of diborane;
continuing the flow of methane for a predetermined time after termination of the diborane;
after the end of flow of the methane, terminating the microwave power; and
cooling the substrate holder to room temperature.
16 . The method of claim 15 wherein the desired thickness of the single crystal boron doped diamond is at least approximately 250 micrometers.
17 . The method of claim 15 wherein the single crystal boron doped diamond has a (100) crystal orientation.
18 . The method of claim 15 wherein the growth rate of diamond is approximately 1 micrometer per hour.
19 . The method of claim 15 and further comprising:
cooling the single crystal boron doped diamond; and
cleaning the single crystal boron doped diamond in a mixture of chromic acid and sulfuric acid at a temperature of approximately 250° C.
20 . A method of growing single crystal diamond, the method comprising:
placing a polished seed in a substrate holder in a microwave plasma reactor;
creating a plasma ball in a hydrogen environment;
heating the substrate holder;
adding methane containing diborane;
after formation of a desired thickness of single crystal boron doped diamond, terminating the flow of diborane and methane;
after the end of flow of the methane, terminating the microwave power; and
stopping heating the substrate holder.
21 . The method of claim 20 wherein the desired thickness of the single crystal boron doped diamond is at least approximately 250 micrometers.
22 . The method of claim 20 wherein the single crystal boron doped diamond has a (100) crystal orientation.
23 . The method of claim 20 wherein the growth rate of diamond is approximately 1 micrometer per hour.
24 . The method of claim 20 and further comprising:
cooling the single crystal boron doped diamond; and
cleaning the single crystal boron doped diamond in a mixture of chromic acid and sulfuric acid at a temperature of approximately 250° C.
25 . A method of growing single crystal diamond, the method comprising:
placing a polished seed in a substrate holder in a microwave plasma reactor;
creating a plasma ball in a hydrogen environment;
heating the substrate holder;
adding methane containing diborane; and
after formation of a desired thickness of single crystal boron doped diamond, terminating the flow of diborane and methane.