Enhancing the bandwidth of a-IGZO TFT amplifiers using circuit design techniques

• Autor(a) principal: Rodrigues, Ricardo Martins Felício Marques
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/89183
• topic: a-IGZO TFT; Unity Current Gain Frequency; Circuit Design Technique; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Amorphous oxide thin-film transistor (TFT) technology has become central in flexible and low-cost electronic applications. However, there are some limitations of the technology for circuit implementation, particularly the lack of stable and reproducible p-type oxide TFTs, limited speed due to poor semiconductor mobility and to large channel lengths when com-pared to single crystalline Si devices. These limitations demand novel circuit design techniques using only n-type TFTs to achieve high-speed circuits meeting the requirement of practical applications. This work aims to improve the low unity current gain frequency of operation of a-IGZO based amplifiers using only circuit-based techniques, without changing the device structure, fabrication steps and materials. Simulations in Cadence environment were performed in five different amplifier structures, employing a-IGZO TFTs based on an in-house model developed with artificial neural networks. Up to three-fold improvement on bandwidth was verified, with minimal increases in power consumption and chip area. The concepts explored here are thus quite relevant to enhance low-MHz range circuits, as required for RFID and biomedical applications.