Ultratough single crystal boron-doped diamond
The invention relates to a single crystal boron doped CVD diamond that has a toughness of at least about 22 MPa m 1/2 . The invention further relates to a method of manufacturing single crystal boron doped CVD diamond. The growth rate of the diamond can be from about 20-100 μm/h.
1. A method for growing single-crystal boron doped diamond of high toughness comprising:
i) placing a seed diamond in a heat sink holder made of a material that has a high melting point and high thermal conductivity to minimize temperature gradients across the growth surface of the diamond;
ii) controlling the temperature of a growth surface of the diamond such that the temperature of the growing diamond crystals is in the range of 1100-1300° C.; and
iii) growing single-crystal diamond by microwave plasma chemical vapor deposition on the growth surface of a diamond in a deposition chamber comprising 5-20% CH 4 /H 2 , 5-20% O 2 /CH 4 , 0-0.2% N 2 /CH 4 and a source of boron,
wherein the growth rate of the diamond is from about 20-100 μm/h,
wherein the orientation of the single-crystal diamond seed is 1-15 degrees off of the {100} plane,
wherein the as-grown diamond is substantially free of silicon in the diamond structure,
wherein the pressure in the deposition chamber is from 150 to 220 torr; and
wherein the toughness of the as-grown diamond is in the range of 22-35 MPa m 1/2 .
2. The method of claim 1 , wherein the source of boron is diborane, hexagonal boron nitride powder, a trimethyl borate gas, vaporized B 2 O 3 , or mixtures thereof.
3. The method of claim 1 , further comprising annealing the single-crystal diamond.
4. The method of claim 1 , wherein the heat sink holder is made of molybdenum.
5. The method of claim 1 , wherein the source of O 2 is carbon monoxide, carbon dioxide, water vapor or mixtures thereof.
6. A single-crystal boron-doped diamond grown by microwave plasma chemical vapor deposition that has a toughness in the range of 22-35 MPa m 1/2 and is grown by a method comprising:
i) placing a seed diamond in a heat sink holder made of a material that has a high melting point and high thermal conductivity to minimize temperature gradients across the growth surface of the diamond;
ii) controlling the temperature of a growth surface of the diamond such that the temperature of the growing diamond crystals is in the range of about 1100-1300 ° C.; and
iii) growing single-crystal diamond by microwave plasma chemical vapor deposition on the growth surface of a diamond in a deposition chamber comprising 5-20% CH 4 /H 2 , 5-20% O 2 /CH 4 , 0-0.2% N 2 /CH 4 and a source of boron,
wherein the growth rate of the diamond is from about 20-100 μm/h,
wherein the orientation of the single-crystal diamond seed is 1-15 degrees off of the {100} plane,
wherein the pressure in the deposition chamber is from 150 to 220 torr; and
and wherein the as-grown diamond is substantially free of silicon in the diamond structure.