Impact of Orientation Misalignments on Black Phosphorus Ultrascaled Field-Effect Transistors

Abstract

Two-dimensional materials with strong bandstructure anisotropy such as black phosphorus (BP) have been identified as attractive candidates for logic application due to their potential high carrier velocity and large density-of-states. However, perfectly aligning the source-to-drain axis with the desired crystal orientation remains an experimental challenge. In this paper, we use an advanced quantum transport approach from first-principle to shed light on the influence of orientation misalignments on the performance of BP-based field-effect transistors. Both n-and p-type configurations are investigated for six alignment angles, in the ballistic limit of transport and in the presence of electron-phonon and charged impurity scattering. It is found that up to deviations of 50 • from the optimal angle, the ON-state current only decreases by 30%. This behavior is explained by considering a single bandstructure parameter, the effective mass along transport direction.

Field‐Effect Transistors Based on 2D Materials

“…Nevertheless, a region where the current is almost insensitive to the misalignment angle can be expected in all cases, as suggested Klinkert et al (2021). If 2-D materials should replace Si as the channel of future field-effect transistors, they should be used during several consecutive technology nodes.…”

“…For example, it is well-known in BP that transport along the Γ-Y axis is (much) less efficient than along Γ-X (Xia et al (2014)). Using the proposed MLWF+NEGF approach, we found in Klinkert et al (2021) that orientation misalignments up to 50 • from the ideal case do not significantly alter the ON-state current of BP transistors, with almost negligible performance loss up to a misalignment angle of 20 • . This means that I ON does not linearly decrease as a function of the misalignment angle, but rather first stays constant up to 20 • , slightly decreases up to 50 • , and finally rapidly drops.…”

Computational perspective on recent advances in quantum electronics: from electron quantum optics to nanoelectronic devices and systems

“…Klinkert et al used a coupled DFT-NEGF approach to investigate the orientation misalignments and their impact on the performance of black phosphorus FETs [337]. N-and p-type configurations were investigated including six alignment angles.…”

Transport and performance study of double-walled black phosphorus nanotube transistors

“…BP applications as the field-effect transistors (FETs) has been extensively studied [16][17][18][19][20][21][22][23][24][25]. The ballistic performance limit of monolayer BP FETs has also been studied [17,18,26,27]. They have reported high on current and high carrier mobility along the armchair direction due to lighter carrier mass.…”

“…Li et al [27] have experimentally studied a 12.5 nm thick BP FET and they have found that interface engineering with high quality HfLaO dielectrics and the channel oriented along the armchair direction can provide high on-state current up to 1.6 mA µm −1 with a ballistic limit up to 79%. Klinkert et al [26] have studied the misalignment between the preferred crystallographic axis (the one with the lowest effective mass) and the source-drain axis. They have found that the on-state current is decreased by only 30% for up to the misalignment angle of 50 • from the optimal direction.…”