Monolayer Hexagonal Boron Nitride Tunnel Barrier Contact for Low-Power Black Phosphorus Heterojunction Tunnel Field-Effect Transistors

Abstract

Transistor downscaling by Moore’s law has facilitated drastic improvements in information technology, but this trend cannot continue because power consumption issues have pushed Moore’s law to its limit. Tunnel field-effect transistors (TFETs) have been suggested to address these issues; however, so far they have not achieved the essential criteria for fast, low-power switches, i.e., an average subthreshold swing over four decades of current (SSave_4dec) below 60 mV/dec and a current of 1–10 μA/μm where the SS is 60 mV/dec (I 60). Here, we report a black phosphorus (BP) heterojunction (HJ) TFET that exhibits a record high I 60 of 19.5 μA/μm and subthermionic SSave_4dec of 37.6 mV/dec at 300 K, using a key material factor, monolayer hexagonal boron nitride tunnel barrier for the drain contact. This work, demonstrating the influence of the tunnel barrier contact on device performance, paves the way for the development of ultrafast low-power logic circuits beyond CMOS capabilities.

Recent Advances in Two‐Dimensional Heterostructures: From Band Alignment Engineering to Advanced Optoelectronic Applications

“…[ 101–105 ] Moreover, such band‐to‐band tunneling (BTBT) is based on cold charge injection mechanism, which can be further utilized to construct tunnel field‐effect transistors (TFETs) with smaller subthreshold swing values (<60 mV dec −1 ) and much lower power consumption (Figure 1m). [ 86,106,107 ]…”

“…also realized the band alignment tuning by inducing local electrostatic doping in BP lateral homojunction. [ 86,106 ] As shown in Figure 4f, the homojunction consists of two parts, bulk BP region and monolayer (ML) BP region, which forms type‐I band alignment at the interface. In such device, by applying appropriate top gate and back gate voltage, the relative band position of monolayer BP can be tuned correspondingly, resulting in tunable band alignment between monolayer BP and bulk BP.…”

Quantum tunneling in two-dimensional van der Waals heterostructures and devices

“…Even a tunnel FET based on vertical vdW heterojunctions has resulted in a promising SS of sub-60 mV dec −1 ; however, interface issues always limit device fabrication and result in experimental results far deviating from theoretical predictions [144]. Another type of 2D tunnel FET employs the traditional p-i-n structure, where a natural heterojunction is formed by spatially varying the thickness in one flake of BP [145,146]. Fig.…”

Device Simulation of The GeSe Homojunction And vdW GeSe/GeTe Heterojunction TFETs For High-Performance Application

“…To further introduce a homojunction or heterojunction architecture [15][16][17][18][19][20][21] in a TFET is a convincing scheme to continuously promote the Ion compared to a homogenous 2D channel. Experientially, 2D TFETs have been fabricated based on transition metal chalcogenides (TMD) and black phosphorene (BP) with good Ion and SS [24][25][26][27][28][29][30][31]. Inspiringly, a much higher Ion is observed on BP homojunction TFETs than their homogenous counterparts from experiment [29][30][31] and theory [18][19][20].…”