“…The multifarious roles of nitrogen addition into CH 4 /H 2 plasma on tailoring the growth of CVD diamond films ranging from large-grained 100 textured to fine grained nanocrystalline have been demonstrated depending either on the amount of N 2 addition or on the other growth parameters (for example, pressure, power, temperature, and methane . [12][13][14][15][16][17][18] For instance, trace amounts of nitrogen addition can facilitate the formation of high-quality large-grained 100 textured diamond at low pressure (N 2 10-200 ppm, CH 4 /H 2 0.5-2%, substrate temperature T subs ∼ 800 C, pressure 50 Torr), 12 while much higher N 2 concentration about 4% has been employed to deposit NCD (a gas mixture of CH 4 /H 2 /N 2 with flow rates of 2∼15/190/8 sccm, respectively, the microwave power was varied between 550 W and 1000 W, the reactant pressure was altered in the range of 13-28 Torr, and the substrate temperature was maintained at 800 C. 18 In this work, we report that NCD films can be produced by employing a new growth parameter window, i.e., using medium amount of N 2 addition (say, 0.24%) under a conventional condition for the growth of a high quality large grained polycrystalline diamond film, say, high microwave power 3000 W, high pressure 105 Torr, 4% methane in H 2 , and substrate surface temperature ∼750 C. Furthermore, by overlapping a small silicon slice on a large silicon wafer of 5.08 cm in diameter to achieve two different substrate temperatures in one single deposition run, both a NCD film grown at low temperature and a 100 textured largegrained diamond film deposit at high temperature can be prepared simultaneously. These new results demonstrate that distinct growth modes were involved or coupled effect of nitrogen addition and temperature happened.…”