RF Equivalent-Circuit Analysis of p-Type Diamond Field-Effect Transistors with Hydrogen Surface Termination

Makoto KASU  Kenji UEDA  Hiroyuki KAGESHIMA  Yoshiharu YAMAUCHI  

IEICE TRANSACTIONS on Electronics   Vol.E91-C   No.7   pp.1042-1049
Publication Date: 2008/07/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.7.1042
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Heterostructure Microelectronics with TWHM 2007)
Category: Wide Bandgap Devices
diamond,  field-effect transistors,  RF characteristics,  equivalent circuit,  hydrogen-surface termination,  

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On the basis of the RF characteristics of p-type diamond field-effect transistors (FETs) with hydrogen surface termination, we establish an equivalent circuit (EQC) model. From comparisons of three cases we reveal that to represent the device performance in the EQC, the source, gate, and drain resistance should be considered but that the gate-source and gate-drain resistance can be ignored. The features of diamond FETs are (1) a plateau of the gate capacitance in a certain gate voltage range. (2) maximum fT and fMAX cut-off frequencies near the threshold gate voltage, and (3) a high fMAX/fT ratio 3.8. We discuss these features in terms of the energy barrier between the gate metal and the two-dimensional hole channel and drift region below the gate.