基底偏压对氮化硼薄膜场发射特性的影响

Influence of Substrate Bias on Field Emission Characteristics of Boron Nitride Thin Films

利用射频磁控溅射方法,在n型(100)Si(0.008~0.02Ω.m)基底上沉积了氮化硼(BN)薄膜.红外光谱分析表明,BN薄膜结构均为六角BN(h-BN)相.在超高真空系统中测量了BN薄膜的场发射特性,发现BN薄膜的场发射特性与基底偏压关系很大,阈值电场随基底偏压的增加先增加后减小.基底偏压为-140V时BN薄膜样品场发射特性要好于其他样品,阈值电场低于8V/μm.F^N曲线表明,在外加电场的作用下,电子隧穿BN薄膜表面势垒发射到真空.

Boron nitride(BN) thin films were prepared on the (100)-oriented surface of n-Si(0.0080.02 Ωm) by means of R.F. magnetron sputtering physical vapor deposition(PVD). There are only two absorption peaks of h-BN at about 1 380 cm^(-1) and 780 cm^(-1) in Fourier transform infrared (FTIR) spectra of the BN thin films. The field emission characteristics of BN thin films were measured in a super high vacuum system. It has been found that the field emission characteristics of BN thin films depended evidently on substrate bias. The threshold electric field increases first and then decreases with substrate bias increasing. The lowest threshold (electric) field is 8 V/μm for the BN film deposited at a substrate bias of -140 V, respectively. It has been shown that electrons are emitted from BN thin film to vacuum tunneling through the potential barrier at the (surface) of BN thin film under exterior electric field by Fowler-Nordheim (F^N) plots.