SUBMICROMETER SILICON PERMEABLE BASE TRANSISTORS WITH BURIED COSI2 GATES

Silicon permeable base transistors (PBTs) with monocrystalline buried CoSi2 gates have been fabricated by local high dose cobalt ion implant ation through a grid-like mask into epitaxial Si (100) layers and homo epitaxial Si overgrowth by low-pressure vapour phase epitaxy. The PBTs show good DC characteristics and pinchoff at zero or at low negative gate voltages, respectively. Transistors with a grating periodicity of 0.6 mum reach a maximum transconductance g(m) of 70 mS/mm. The highes t obtained transit frequency is f(T) = 6 GHz.