Effect of the hexagonal phase interlayer on rectification properties of boron nitride heterojunctions to silicon

摘要

Rectification properties of boron nitride/silicon p-n heterojunction diodes fabricated under low-energy ion impact by plasma-enhanced chemical vapor deposition are studied in terms of the resistive sp~2-bonded boron nitride (sp~2BN) interlayer. A two-step biasing technique is developed to control the fraction of cubic boron nitride (cBN) phase and, hence, the thickness of the sp~2BN interlayer in the films. The rectification ratio at room temperature is increased up to the order of 10~4 at ±10V of biasing with increasing the sp~2BN thickness up to around 130 nm due to suppression of the reverse leakage current. The variation of the ideality factor in the low bias region is related to the interface disorders and defects, not to the sp~2BN thickness. The forward current follows the Frenkel-Poole emission model in the sp~2BN interlayer at relatively high fields when the anomalous effect is assumed. The transport of the minority carriers for reverse current is strongly limited by the high bulk resistance of the thick sp~2BN interlayer, while that of the major carriers for forward current is much less affected.