Effect of dc bias on the compositional ratio of WNX thin ®lms prepared by rf-dc coupled magnetron sputtering

The effect of the dc bias on the compositional ratio, resistivity, and deposition rate for tungsten nitride (WNX) ®lms prepared by rf-dc coupled magnetron sputtering have been investigated in detail. The value of the ®lm compositional ratio (N/ W) is signi®cantly decreased from 0.8 to 0.2 with increasing the target dc bias voltage. The increase of the target dc bias voltage from ÿ100 to ÿ500 V results in a dramatical decrease in the resistivity of WNX ®lms. It is shown that the N/W ratio and the resistivity of WNX thin ®lms deposited at the target dc bias voltage of ÿ200 V are about 0.5 and 370 mO cm, respectively. # 2001 Elsevier Science B.V. All rights reserved.