No assignee for this patent application has been made.
News editors obtained the following quote from the background information supplied by the inventors: "The invention relates to a high voltage metal-oxide-semiconductor (herein after abbreviated as HV MOS) device, and more particularly, to a high voltage lateral double-diffused metal-oxide-semiconductor (HV-LDMOS) device.
"Double-diffused MOS (DMOS) transistor devices have drawn much attention in power devices having high voltage capability. The conventional DMOS transistor devices are categorized into vertical double-diffused MOS (VDMOS) transistor device and lateral double-diffused MOS (LDMOS) transistor device. Having advantage of higher operational bandwidth, higher operational efficiency, and convenience to be integrated with other integrated circuit due to its planar structure, LDMOS transistor devices are prevalently used in high operational voltage environment such as CPU power supply, power management system, AC/DC converter, and high-power or high frequency (HF) band power amplifier. The essential feature of LDMOS transistor device is a lateral-diffused drift region with low dope concentration and large area. The drift region is used to alleviate the high voltage between the drain and the source, therefore the LDMOS transistor device can have higher breakdown voltage.
"Please refer to FIG. 1, which is a cross-sectional view of a conventional HV-LDMOS transistor device. As shown in FIG. 1, the conventional HV-LDMOS transistor device 10 having a p-type well 20, a source 14 and a p-type heavily doped region 22 formed in the p-type well 20, a gate 16 and a drain 18 is formed on a semiconductor substrate 12. The drain 18 is an n-type heavily doped region formed in an n-type well 30, which is the drift region as mentioned above. The dope concentration and length of the drift region affects the breakdown voltage and the ON-resistance (R.sub.ON) of the HV-LDMOS transistor device 10. The gate 16 of the HV-LDMOS transistor device 10 is positioned on a gate dielectric layer 40 and extended to cover a portion of a field oxide layer 42.
"It is well-known that characteristics of low R.sub.ON and high breakdown voltage are always required to the HV MOS transistor device. However, breakdown voltage and R.sub.ON are conflicting parameters with a trade-off relationship. Therefore, a HV LDMOS transistor device that is able to realize high breakdown voltage and low R.sub.ON is still in need."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "According to the claimed invention, a HV MOS transistor device is provided. The HV MOS transistor device includes a substrate, a gate formed on the substrate, a source region and a drain region formed in the substrate at respective sides of the gate, and a first isolation structure formed under the gate. The first isolation structure is overlapped by the entire gate.
"According to the claimed invention, a HV MOS transistor device is further provided. The HV MOS transistor device includes a substrate, a gate positioned on the substrate and extending along a first direction, a plurality of drift regions formed in the substrate, and a plurality of first isolation structures formed in the substrate. The drift regions are arranged along the first direction. Each of the first isolation structures extends along a second direction, and the second direction is perpendicular to the first direction. The gate covers a portion of each drift region and a portion of each first isolation structure, and the drift regions and the first isolation structures under the gate are alternately arranged along the first direction.
"According to the HV MOS transistor device provided by the present invention, the first isolation structure is provided to be overlapped by the entire gate, therefore the breakdown voltage is improved without increasing R.sub.ON.
"These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
"FIG. 1 is a cross-sectional view of a conventional HV-LDMOS transistor device.
"FIG. 2 is a schematic drawing of a portion of a layout pattern of a HV MOS transistor device provided by a first preferred embodiment of the present invention.
"FIG. 3 is a cross-sectional view of the HV MOS transistor device taken along line A.sub.1-A.sub.1' of FIG. 2.
"FIG. 4 is a cross-sectional view of the HV MOS transistor device taken along line B.sub.1-B.sub.1' of FIG. 2
"FIG. 5 is a schematic drawing of a portion of a layout pattern of a HV MOS transistor device provided by a second preferred embodiment of the present invention.
"FIG. 6 is a cross-sectional view of the HV MOS transistor device taken along line A.sub.2-A.sub.2' of FIG. 5.
"FIG. 7 is a cross-sectional view of the HV MOS transistor device taken along line B.sub.2-B.sub.2' of FIG. 5.
"FIG. 8 is a schematic drawing of a portion of a layout pattern of a HV MOS transistor device provided by a third preferred embodiment of the present invention."
For additional information on this patent application, see: Chen, Chin-Fu. High Voltage Metal-Oxide-Semiconductor Transistor Device. Filed
Keywords for this news article include: Patents, Electronics, High Voltage, Semiconductor.
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