The InGaN/GaN films were grown by metalorganic chemical vapor deposition (MOCVD) at atmospheric pressure. Properties of these films

such as their chemical component

thickness

the crystalline quality

and optical properties

were investigated by Rutherford backscattering / channeling measurement and photoluminescence measurement. The growth was carried on (0001) oriented sapphire substrates. TEGa

TMGa

TMIn

and blue ammonia (NH

3

) were used as Ga

In

N precursors

respectively. Before the growth

a thin buffer layer with thickness of about 15nm was deposited at 520℃ and crystallized at 1060℃ for 6 minutes. In the growth of this layer

the / ratio in gas phase was adjusted to achieve good quality of GaN films and prevent the cracks usually occurred. GaN films were grown at 1060℃. After growth

the temperature was decreased to 650～800℃ to growIn

x

Ga

1-x

N layers. Two In

x

Ga

1-x

N samples were discussed in this paper. During the growth

the flow rates of NH

3

TMIn

and TEGa were 1 l/min

2 8μmol/min and 1 6μmol/min

respectively. The growth temperature was 760℃ and N

2

was used as main carrier gas. Sample A used 70ml/min H

2

as the carrier gas of metalorganic precursors

but sample B used 70ml/min N

2

. The In mole fraction and growth rate of In

x

Ga

1-x

N films were largely influenced by the carrier gas in metalorganic precursors when the main carrier gas was N

2

. The In mole fraction in In

x

Ga

1-x

N alloys was 0 10 in sample B. However

the x value was 0.06 in sample A. It means that H

2

can largely influence the In mole fraction in In

x

Ga

1-x

N films

even the flow rate of H

2

was very small. This result is in agreement with other reports. The value of the growth rate was 10 6nm/min for sample A

and that was 6 0nm/min for sample B. This phenomena

the dependence of the InGaN growth rate on little precursors carrier gas H

2

have never been reported to our knowledge. We considered that InN can reduce the lifetime of the reactive In atoms at the film surface during growth

which lead to the increasing of Ga atoms in the film surface. So

the growth rate of alloys increased.