Title:

A novel trench lateral power MOSFET with high breakdown voltage and low on-resistance

Issue Date: 1998
Abstract (summary): This thesis deals with lateral power MOSFETs which are used in disc drives, power supplies, and automotive applications. Power MOSFETs are popular because of their high switching speed, high input impedance and wide safe operating area. However, reduction in device specific on-resistance is limited in conventional lateral DMOS transistors due to the long drift region associated with the drain. The objective of this thesis is to propose a novel power MOSFET to solve the problem. A novel Trench Lateral Power MOSFET (TLPM) and its fabrication process are proposed in this thesis. The TLPM is implemented along the sidewall of trenches in order to increase packing density of the MOSFET. The process utilizes self-aligned method to form the gate electrode and the trench bottom contact holes to the drain to achieve minimum pitch and very low on-resistance. Simulation results show that the proposed TLPM with a device pitch of 4 $\mu$m has a similar current handling capability to a Conventional LPM (CLPM) with a device pitch of 8 $\mu$m for devices with breakdown voltage of 80 V, indicating drastic improvement of specific on-resistance for the TLPM. Experimental verification proves that the unique self-aligned method to open trench bottom contact holes to the drain leads to reduced device pitch. The results show that the specific on-resistances for the TLPM and CLPM are 0.8 m$\Omega$-cm$\sp2$ and 1.6 m$\Omega$-cm$\sp2$ respectively for a 80 V breakdown device.
Content Type: Thesis

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https://hdl.handle.net/1807/12197

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