P‐2: High‐Performance LTPO TFT‐LCD Using Metal as Hydrogen Barrier Layer

Abstract

Low‐Temperature Poly‐Si and Oxide (LTPO) thin‐film transistors (TFTs) have been successfully manufactured and adapted to 6.3 inch liquid crystal display (LCD) panels. To avoid the introducing of hydrogen (H) to oxide TFTs when passivating the Poly‐Si TFTs, the metal barriers are used to prevent the diffusion of hydrogen from the bottom layers. It is shown that those oxide TFTs built with metal barriers exhibit improved intrinsic resistance against hydrogen‐induced degradation. The optimum processes conditions have been used on the 6.3 inch LTPO LCD with ultra‐wide frame rate from 1 to 120 Hz. Further, the specifications of the prototype displays for 409‐ppi LCD with low power consumptions and superior flicker under 1‐Hz frame‐rate driving are reported.

Compact Integration of Hydrogen–Resistant a–InGaZnO and Poly–Si Thin–Film Transistors

“…However, the ∆V th of 20-µm-L TFT shifted to −12.7 V, and the 5-µm-L channel was still shorted. Such an apparent short-channel effect (SCE) reveals that the channel-carrier concentration is gradually increased by the lateral H diffusion; this evidence is consistent with the perfect H-blocking capability of the top metal gate [19].…”

Thermal Dehydrogenation Impact on Positive Bias Stability of Amorphous InSnZnO Thin-Film Transistors

“…In addition, during the fabrication process of LTPO, concerns arise regarding the degradation of electrical performance and bias stability in oxide semiconductors due to the inflow and outflow of hydrogen resulting from the LTPS passivation and gate insulator deposition processes. 13,16,17 Hydrogen plays a dual role in oxide semiconductors, passivating interface defects, 18,19 oxygen vacancies, and weakly bonded states while also generating hydroxyl-related defects and simultaneously causing the formation of oxygen vacancies and donor-like defects, which results in excessive carrier and threshold voltage shift. 20 Despite being one of the most crucial factors in altering the properties of oxide semiconductors, hydrogen is highly reactive and the lightest atom, making it challenging to control the electrical characteristics through quantitative analysis.…”

“…Combining LTPS TFTs with AOS TFTs makes it possible to achieve both high refresh rates and low leakage current, making LTPO a promising driving method for UHR displays. , However, for UHR display panels intended for head-mounted display applications, at least 3000 PPI or higher pixel density is required. , Therefore, there is a growing demand for oxide semiconductor TFTs that not only exhibit low off-current characteristics but also possess a higher mobility and stable bias stability. In addition, during the fabrication process of LTPO, concerns arise regarding the degradation of electrical performance and bias stability in oxide semiconductors due to the inflow and outflow of hydrogen resulting from the LTPS passivation and gate insulator deposition processes. ,, Hydrogen plays a dual role in oxide semiconductors, passivating interface defects, , oxygen vacancies, and weakly bonded states while also generating hydroxyl-related defects and simultaneously causing the formation of oxygen vacancies and donor-like defects, which results in excessive carrier and threshold voltage shift . Despite being one of the most crucial factors in altering the properties of oxide semiconductors, hydrogen is highly reactive and the lightest atom, making it challenging to control the electrical characteristics through quantitative analysis.…”