Document Type : Research Article

Authors

• Carsten Strobel ¹
• Carlos Chavarin ²
• Sebastian Leszczynski ¹
• Karola Richter ³
• Martin Knaut ¹
• Johanna Reif ¹
• Sandra Voelkel ¹
• Matthias Albert ¹
• Christian Wenger ⁴
• Johann Wolfgang Bartha ¹
• Thomas Mikolajick ¹

¹ Institute of Semiconductors and Microsystems, Chair of Nanoelectronics, Technische Universität Dresden, Nöthnitzer Straße 64, 01187 Dresden, Germany

² IHP - Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany

³ Institute of Semiconductors and Microsystems, Electrical Engineering, Technical University of Dresden, Dresden, Germany

⁴ BTU Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus, Germany

Abstract

A new kind of transistor device with a graphene monolayer embedded between two n-type silicon layers is fabricated and characterized. The device is called graphene-base heterojunction transistor (GBHT). The base-voltage controls the current of the device flowing from the emitter via graphene to the collector. The transit time for electrons passing by the ultrathin graphene layer is extremely short which makes the device very promising for high frequency RF-electronics. The output current of the device is saturated and clearly modulated by the base voltage. Further, the silicon collector of the GBHT is replaced by germanium to improve the device performance. This enabled the collector current to be increased by almost three orders of magnitude. Also, the common-emitter current gain (I_c/I_b) increased from 10^-3 to approximately 0.3 for the newly designed device. However, the ON-OFF ratio of the improved germanium based GBHT has so far been rather low. Further optimizations are necessary in order to fully exploit the potential of the graphene-base heterojunction transistor.  
 

Keywords

• Amorphous silicon
• Graphene
• germanium
• high-frequency
• transistor

Main Subjects

• Carbon Materials and Technology
• Nanomaterials & Nanotechnology