基底偏压对氮化硼薄膜场发射特性的影响

利用射频磁控溅射方法, 在n型（100）Si（0.008～0.02 Ω·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-140 V时BN薄膜样品场发射特性要好于其他样品, 阈值电场低于8 V/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.

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

Boron nitride(BN) thin films were prepared on the (100) -oriented surface of n-Si(0.008～0.02 Ω·m) by means of R.F. magnetron sput tering 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 characteristic s of BN thin films were measured in a super high vacuum system. It has been foun d 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 ha s been shown that electrons are emitted from BN thin film to vacuum tunneling th rough the potential barrier at the surface of BN thin film under exterior el ectric field by Fowler-Nordheim (F~N) plots.