IEEE Transactions on Electron Devices · 1992 · 37 citations · 7 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsBipolar Junction TransistorsCarrier TransportDopingSemiconductor Device MaterialsSemiconductor PhysicsSilicon MaterialsCarrier ConcentrationCarrier GasesCarrier GenerationSemiconductor DopingShallow Junction FormationSilicon DopingThermal DiffusionUltra-shallow Junction Engineering
A novel doping method called rapid vapor-phase direct doping (RVD) is developed to form ultra-shallow junctions. The base region of a conventional bipolar transistor is formed by this method, and in ultra-narrow 25-nm base is obtained. The Gummel plot of this device shows almost ideal characteristics. This result suggests that this method does not induce any defects which cause a leakage current. RVD is a thermal diffusion method using hydrogen as a carrier gas and B/sub 2/H/sub 6/ as a source gas. In this method, the impurity atoms directly diffuse from the vapor phase into silicon by a rapid thermal process without a boron-glass layer or metallic boron layer. By varying the source gas flow rate, doping time, and temperature, ultra-shallow junctions below 40 nm with controlled surface concentrations are successfully formed. An ultra-shallow 20-nm junction with surface boron concentration of 4*10/sup 18/ cm/sup -3/ is obtained at 800 degrees C for 5 min with B/sub 2/H/sub 6/ flow rate of 30 ml/min.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
7