Fabrication of Vertical InGaAs Channel Metal--Insulator--Semiconductor Field Effect Transistor with a 15-nm-Wide Mesa Structure and a Drain Current Density of 7 MA/cm2

We proposed a vertical InGaAs channel metal--insulator--semiconductor field effect transistor (MISFET) with an ultranarrow mesa structure, an undoped channel, and a heterostructure launcher. With the aim of obtaining a narrow mesa structure, we proposed the concept of performing selective undercut etching after dry etching. We fabricated the proposed device with a 60-nm-long and 15-nm-wide channel mesa structure. In the fabricated device, the observed drain current density was 1.1 A/mm. Because the channel mesa width was 15 nm, the drain current density per unit area was 7 MA/cm 2 . Thus, a high current density was achieved for an ultranarrow mesa structure.