Influence of trenching effect on the characteristics of buried-gate SiC junction field-effect transistors

• Two different structures of junction field-effect transistors in 4H-SiC, with and without trenching effect in the channel region, have been fabricated and characterized. The devices formed with metal mask show a trenching profile (>similar to0.2 mum) after dry etch in the channel groove region and exhibited static induction transistor (SIT)-like characteristics in the sub-threshold region of I-V curves as the channel thickness decreases. The devices without trenching effect have been processed by using a wet-etched oxide mask resulting in a sloped dry-etch profile (theta=similar to30degrees) in the channel, and consequently showed well-saturated drain characteristics for all the channel thicknesses. The conduction mechanisms in these JFETs are examined by the potential profiles from two dimensional numerical simulations.

Nyckelord

dry etching

JFETs

SiC

trenching effect

TECHNOLOGY

TEKNIKVETENSKAP

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