| 摘要 |
PURPOSE: High voltage LDMOS in which on-resistance of elements is minimized is provided. CONSTITUTION: The LDMOS comprises a P-type semiconductor substrate(200), a N-type well area(210), a N-type epitaxial layer(214), a N-type buried layer(212) with high doping concentration formed between the well area and the epitaxial layer, a P-type body area(220), a N-type drain area(232) and a gate conductive film(240). The method comprises a step of forming the well area on the semiconductor substrate, a step of forming buried layer on surface of the well area, a step of depositing the epitaxial layer on front surface of the resulted product, and a step of forming insulation area on the epitaxial layer of the semiconductor substrate which has no well area. Such LDMOS can minimize the on-resistance of elements by further comprising buried layer of high concentration in drain drift area to flow current to the buried layer. Also, by modulating the concentration of the buried layer, it is possible to obtain desired withstanding voltage. Thus, breakdown phenomenon is occurred in bulk to improve recovery ability of elements and reliability.
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