A high-density low on-resistance trench lateral power MOSFET with a trench bottom source contact

A novel trench lateral power MOSFET with a trench bottom source contact (TLPM/S) is proposed, fabricated, characterized, and compared with the equivalent TLPM with a trench bottom drain contact (TLPM/D). The TLPM/S is formed along the sidewalls of the trenches so as to reduce the device pitch and realize very small on-resistance per unit area. A total of eight masks are used for fabricating the device. Since the gate electrode and the trench bottom source contact are formed by self-aligning to the trench sidewalls, the device pitch is reduced. Using a line width of 0.6 μm, the fabricated TLPM/S, whose device pitch is 3.0 μm, exhibits a specific on-resistance of 60 mΩ-mm² for a breakdown voltage of 73 V, which is close to the estimated silicon limit for this voltage class of devices. Due to reduced Miller capacitance, the TLPM/S exhibits excellent switching performance, and is approximately 50% faster than the equivalent TLPM/D.