Sanken Electric Co., Ltd.

Polar Semiconductor, Inc.

Polarfab, LLC

Steve Kosier

Peter West

Don Rankila

Tatsuya Kamimura

John Charles Beckman

Dosi Dosev

Sandhya Gupta

Apparatus and associated methods relate to a bond-pad structure having small pad-substrate capacitance for use in high-voltage MOSFETs. The bond-pad structure includes upper and lower polysilicon plates interposed between a metal bonding pad and an underlying semiconductor substrate. The lower polysilicon plate is encapsulated in dielectric materials, thereby rendering it floating. The upper polysilicon plate is conductively coupled to a source of the high-voltage MOSFET. A perimeter of the metal bonding pad is substantially circumscribed, as viewed from a plan view perspective, by a perimeter of the upper polysilicon plate. A perimeter of the upper polysilicon plate is substantially circumscribed, as viewed from the plan view perspective, by a perimeter of the lower polysilicon plate. In some embodiments, the metal bonding pad is conductively coupled to a gate of the high-voltage MOSFET. The pad-substrate capacitance is advantageously made small by this bond-pad structure.

High-voltage MOSFET structures

An integrated circuit having very low parasitic current gain includes a guard ring that is used to completely surround a device, such as a power device, that induces parasitic current. The guard ring is formed in a semiconductor body layer such as an epitaxial layer and has a central guard ring of the same type conductivity as that of the body layer and additional flanking rings of the opposite type conductivity. An unbiased configuration of the guard ring based on the above structure is particularly effective in reducing the parasitic gain. The effectiveness of the guard ring, such as the high current performance, is further improved by reducing the resistance between neighboring rings using various methods.

Guard ring structure for reducing crosstalk and latch-up in integrated circuits

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Lakeville, MN, United States of America

Steve Kosier