Chih-Pang Chang

Improved Electrical Characteristics and Reliability of MILC Poly-Si TFTs Using Fluorine-Ion Implantation

In this letter, fluorine-ion (F+) implantation was employed to improve the electrical performance of metal-induced lateral-crystallization (MILC) polycrystalline-silicon thin-film transistors (poly-Si TFTs). It was found that fluorine ions minimize effectively the trap-state density, leading to superior electrical characteristics such as high field-effect mobility, low threshold voltage, low subthreshold slope, and high on/off-current ratio. F+-implanted MILC TFTs also possess high immunity against the hot-carrier stress and, thereby, exhibit better reliability than that of typical MILC TFTs. Moreover, the manufacturing processes are simple (without any additional thermal-annealing step), and compatible with typical MILC poly-Si TFT fabrication processes.

Improved Electrical Performance and Uniformity of MILC Poly-Si TFTs Manufactured Using Drive-In Nickel-Induced Lateral Crystallization

A new manufacturing method for polycrystalline silicon (poly-Si) thin-film transistors (TFTs) using drive-in nickel-induced lateral crystallization (DILC) was proposed. In DILC, a F+ implantation was used to drive Ni in the alpha-Si layer. To reduce Ni contamination, the remained Ni film was then removed and subsequently annealed at 590 degC. It was found that DILC TFTs exhibit high field-effect mobility, low threshold voltage, low subthreshold slope, high on-state current, lower trap-state density, smaller standard deviations, and low off-state leakage current compared with conventional Ni-metal-induced lateral crystallization TFTs.

Improved Electrical Performance of MILC Poly-Si TFTs Using

In this letter, a new manufacturing method for metal-induced lateral crystallization (MILC) polycrystalline silicon thin-film transistors (poly-Si TFTs) using CF4 plasma was proposed. It was found that CF4 plasma effectively minimizes the trap-state density by etching away the top surface of MILC and passivating the trap states, leading to superior electrical characteristics such as high field-effect mobility, low threshold voltage, low subthreshold slope, low leakage current, and high ON-/ OFF-current ratio. CF4-plasma MILC TFTs also possess high immunity against the hot-carrier stress and thereby exhibit better reliability than that of conventional MILC TFTs. Moreover, the manufacturing processes are simple (without any additional thermal annealing step) and compatible with MILC TFT processes.

\hbox{CF}_{4}

In this study, a CF 4 plasma etching treatment was applied to metal-induced lateral crystallization (MILC) polycrystalline silicon thin film transistors (poly-Si TFTs). It was found that the electrical properties and reliability of the MILC poly-Si TFTs were improved by the treatment. The minimum off-state currents were also reduced. This is because this etching method involves not only passivating the trap states but also etching away the Ni-related defects on the top surface of MILC poly-Si.

Plasma by Etching Surface of Channel

Abstract Electrical characteristics of oxide/nitride/oxide(ONO) capacitors using two polysilicon gates deposited by low pressure chemical vapor deposition (LPCVD) at two different temperatures (560 °C, 620 °C) were investigated and compared. It was found that the quality of polysilicon is important for the electrical characteristics of ONO capacitors. The as-deposited film deposited at 560 °C is amorphous, whereas the film deposited at 620 °C is polycrystalline. After heat treatment, the film deposited at 560 °C demonstrates a preferred orientation along (111), which is different from the (220) preferred orientation of the film deposited at 620 °C. Better electrical characteristics, including lower sheet resistance, higher mobility and dopant activation were observed on the films deposited at 560 °C after heat treatment. With a higher quality polysilicon gate, the electrical characteristics of ONO capacitors using a low temperature deposited polysilicon gate doped by phosphorus implantation are superior to those of ONO capacitors using a POCl3 doped low temperature (560 °C) deposited gate or a POCl3 doped high temperature (620 °C) deposited gate.

Effect of CF4 Plasma on Properties and Reliability of Metal-Induced Lateral Crystallization Silicon Transistors

In this study, polycrystalline silicon thin film transistors using drive-in Ni induced lateral crystallization (DILC) was proposed. In DILC, F + implantation was used to drive Ni in the α-Si layer. To reduce the Ni contamination, the remained Ni film was then removed, and subsequently annealed at 590°C. It was found DILC TFTs exhibit high field-effect mobility, low threshold voltage, low subthreshold slope, high on-state current, lower trap state density, smaller standard deviations, and low off-state leakage current compared with conventional Ni-metal-induced lateral crystallization (MILC) TFTs.