Design and Analysis of Power Low-Temperature Polysilicon Lateral Double-Diffusion Metal Oxide Semiconductor Field Effect Transistors with Shielding-Trench Structure

Abstract

A new polycrystalline silicon (poly-Si) lateral double-diffusion metal oxide semiconductor field-effect transistor power device combining super-lateral-growth technology and shielding-trench oxide structures (STO-LDMOSFET) is introduced. The trench oxide offers a platform for amorphous silicon lateral growth through excimer laser annealing; this not only enables stable control of the crystallization of poly-Si but also promotes the blocking ability of devices. The breakdown voltages of the manufactured devices with and without trench oxide are 460 and 387 V, respectively, increasing by approximately 73 V. The characteristics of poly-Si treated with an excimer laser were obtained by low-temperature poly-Si LDMOSFET (LTPS-LDMOSFET) measurement and simulation. Then, STO-LDMOSFETs were studied by simulation. The results showed that the STO-LDMOSFET with a 150 cm2 V-1 s-1 mobility had a breakdown voltage and a specific on-resistance of approximately 450 V and 16 Ω cm2, respectively, at a 40 µm drift region length.