- Low Voltage Dual-Well MOS Device Having Ruggedness Low On-Resistance and Improved Body Diode Reverse Recovery

摘要

PURPOSE: A low-voltage MOS device is provided to obtain high durability and low resistance and to improve main body diode reverse recovery characteristic. CONSTITUTION: An upper layer(102) doped lightly into an N-type is formed on a single-crystal silicon substrate(101), and a further a blanket(103) doped heavily in N-type is made. An insulating layer(106) and a conductive layer(107) are stacked as a gate(105), and each layer is doped in the order of N-type and P-type from an opening (110) to fuse itself with the blanket(103), thus an N-well(108), a P-well(109), and under the gate(105), an N neck region(111) are made. Next, a P-well(112) and an N-source(113) are made by the implantation of P-type and N-type dopant, and a dielectric film(115) and a source metal(114) are deposited. As a result, a parasitic BJT function made of the junction of the N+-source, the P-well, and the N-well/the N-epitaxial layer is reinforced, and the electron diffusing current in the P-well increases, and minority charges accumulated in the N-epitaxial layer and the P-well decrease.