First of all for magnetron sputtering the conventional operating pressure is 3-10 mTorr. So, first you have to use Argon so that the chamber pressure is about 3 or 4 mTorr. Then slowly vary the oxygen flow rate.

Further, temprature of the substrate arizes due to severe ion bombardment and your high pressure conditions (70 sccm of Ar is too much).

So, you may work at low pressure 3 mtorr (Argon) + add oxygen so that the pressure to be within 10 mTorr. Also, you may use RF high power up to 1 KW for higher plasma density that will enhance your deposition rate with higher discharge current, and help in sputtering of C atoms from the target.

Good luck.

You have a simple question "What is sputtering", and you need some good literature to read about it.

1) Sputtering technique involves ejecting out specie (atomic or molecular) from a target by ionic bombardment. Ions are produced by electrical discharge in a vacuum chamber at a certain pressure.

    Let us say you want to make a Copper film on a glass plate. 

    i) Firstly you will have a Copper disc (1" to 4") in diameter, and thickness about 1 to 4 mm. This is known as the target.

    ii) You need to bombard this target with ions. In order to produce ions, you need to create a discharge.  It is good to have inert gas ions such as (Ar+) ions so that they don't react with the copper.

there are two types of sputtering DC and Rf, let's understand DC sputtering first.

   iii) In order to do DC sputtering you will produce a DC discharge generated by a DC voltage. The discharge is produced between two electrodes.

   (iv) You will make the Cu disc (target) as one of the electrodes, this is insulated with the body, and you will have another dummy electrode. You apply the -ve voltage to the Cu disc, and positive wire to the dummy electrode. At a certain voltage (high kilo volts 3000 to 4000). These electrodes are placed in a vacuum chamber. You creat vacuum, and then introduce argon gas, and raise the pressure to the range (10-2 to 10-3 Torr). When you apply the DC volts, the gas will breakdown, you will now have electrons and positive Argon ions. the +ve Ar ions will runs to the Cu disc which is negatively charged. The rushing +ve Argon ions have both momentum and charge. The charge will be neutralised, and the momentum will be transferred to the copper disc. This will allow the ejection of Cu atoms from the surface of the Copper disc (known as the target).

In other words the whole process is known as sputtering of Copper.

2) You should now read some good books to know a\more about sputtering.

     i) Handbook of thin film technology by Maissel and Glang

    ii) Glow discharge phenomena by Brian chapman.

3) Any general book on Thin film technology also should explain what is sputtering, and on the web also you will find lots of informative discussion on sputtering.

    It is difficult to suggest journal papers on this subject. Rather reading good books by well known authors is more advisable to learn more about Sputtering.

K. Sreenivas 

Many Thanks for the kind response @ K. Sreenivas

Thanks Kaylan