Effect of Dopant Concentration in Lightly Doped Drain Region on the Electrical Properties of N-Type Metal Induced Lateral Crystallization Polycrystalline Silicon Thin Film Transistors

Abstract

In this study, the effect of dopant concentration in lightly doped drain (LDD) region on the electrical properties of N-type gate insulator doping mask (GIDM) LDD metal-induced lateral crystallization (MILC) polycrystalline silicon thin film transistors (TFTs) was investigated. In order to find the optimum value for the dopant concentration in LDD region, we analyzed the electrical properties of LDD MILC TFTs with different dopant concentration in LDD region. The dopant concentrations in LDD regions of the TFTs were measured using secondary ion mass spectroscopy (SIMS). From the electrical properties and the SIMS data of the TFTs, it has been found that for the N-type GIDM LDD MILC TFTs with the LDD length of about 1.5 µm, the dopant concentration in LDD region should be in the range between 1019 and 3×1020/cm3 to ensure the suppression of off-state leakage current without device performance degradation.