工作气压对氮化硼薄膜场发射特性的影响

Influence of work gas pressure on field emission characteristics for BN thin films

利用射频磁控溅射方法,在n型(100)Si基底上沉积了氮化硼(BN)薄膜,并在超高真空系统中测量了BN薄膜的场发射特性.研究发现,沉积时工作气压的变化对BN薄膜的场发射特性有很大影响,工作气压为2Pa时沉积的BN薄膜样品的场发射特性较好,其阈值电场为6V/μm,场发射电流为320μA/cm2.F-N曲线表明,在外加电场的作用下,电子是通过隧道效应穿透BN薄膜表面势垒发射到真空的.

BN thin films were prepared on the (100)-oriented surface of n-Si by r.f.magnetic sputtering physical vapor deposition(PVD). The field emission characteristics of thin BN films were measured in a super high vacuum system. It is found that the field emission characteristics of thin BN films is affected evidently by total pressure changing. A turn-on electric field as low as 6?V/μm is obtained and the highest emission current density is 320?μA/cm^2 for BN film (deposited) at total work gas pressure of 2?Pa. F-N curves indicate that electrons are transfered from substrate Si to conduction band of BN thin film and are emitted from BN to vacuum (tunneling) through the potential barrier at the surface of the BN thin film under exterior electric field action.