Vertical Graphene Base Transistor

Abstract

We present a novel, graphene-based device concept for high-frequency operation: a hot electron graphene base transistor (GBT). Simulations show that GBTs have high current on/off ratios and high current gain. Simulations and small-signal models indicate that it potentially allows THz operation. Based on energy band considerations we propose a specific materials solution that is compatible with SiGe process lines.Comment: 9 pages, 3 figures; IEEE Electron Device Letters, Vol.33, Issue 5, (2012

Resonant plasmonic terahertz detection in vertical graphene-base hot-electron transistors

“…The comparison of the GB-HETs [1][2][3][4] and InPDHBTs [51][52][53] with the GB-HETs under consideration highlights the following advantages of the latter: (i) a longer momentum relaxation time of holes τ in the GB; (ii) a higher plasma-wave velocity s that enables higher resonant plasma frequencies; (iii) a smaller capture probability of hot electrons into the GB and, consequently, larger (or even much larger) fraction of the hot electrons reaching the collector; (iv) coupling the incoming THz signal to the GB resulting in the absence of the ac current in the emitter-collector circuit and prevanting the RC effects usually hindering the high-frequency operation.…”

“…Recently, vertical hot-electron transistors (HETs) with the graphene base (GB) and the bulk emitter and collector separated from the base by the barrier layersthe hot-electron graphene-base transistors (GB-HETs) -made of SiO 2 and Al 2 O 3 were fabricated and studied [1][2][3][4]. These HETs are fairly promising devices despite their modest characteristics at the present.…”

Electrical Compact Modeling of Graphene Base Transistors

“…Hence, the choice of the material used for the EBi and BCi region is of major importance. EBi and BCi can be either an insulator material such as SiO2 or high-k dielectrics to exploit a tunneling transport [6] or a semiconductor such as Ge or Si to foster a thermionic current [12]. According to the transistor structure (see Figure 1), the following equivalent circuit is proposed (see Figure 2).…”

“…Unfortunately, the lack of energy bandgap in graphene induces poor DC electrical characteristics and GFETs are still under evaluation [4] and optimization. Also, new transistor concepts are explored such as the Graphene Barristor [5] or the hot electron graphene base transistor (GBT) [6,7]. As explained by the inventors [7], compared to the GFET where the carrier transport is within the plane of the graphene sheet, "the GBT is based on a vertical arrangement of emitter (E), base (B), and collector (C), just like a hot electron transistor or a vacuum triode".…”

“…A small signal model has been proposed in [6]. In order to evaluate this transistor in circuit configuration, a large signal compact model is necessary.…”