Study on the Characteristics Distributions of LPTS TFTs for Circuit Simulation

• Main Authors: Guo-Feng Peng, 彭國烽
• Other Authors: Jyh-Long Chern
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/08197126000838973372

碩士 === 國立交通大學 === 光電工程系所 === 94 === Low Temperature Polycrystalline Silicon (LTPS) thin film transistors (TFTs) have attracted much attention in the application on the integrated peripheral circuits of display electronics such as active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting diodes (AMOLEDs) due to its better current driving compared with a-Si (amorphous silicon) TFTs. In this thesis, the variation characteristics of LTPS TFTs are statistically investigated. The differences of the threshold voltage and mobility with the same device distance are further studied. The difference shows the distribution much centered than the Gaussian distribution and a proper model is proposed to describe the variation behaviors with difference device distances, for which the R squares (Coefficient of Determination) are higher than 0.95, reflecting the validity of the model. Furthermore, the proposed models are used to simulate the performance of the differential pair and current mirror circuit, which are commonly used in VLSI. Simulation results show the effects of the variation behavior on the estimation of the circuit performance. Besides, from the simulation results, it is found that the Gaussian distributions defined by the inter-quartile range of parameters difference data have a good fitness for the real data distribution compared with Gaussian distribution defined by the standard deviation. Therefore, Monte Carlo analysis with Gaussian distribution still can be used to simulate LTPS TFT circuits in simulation tools. Furthermore, the circuit simulation results will be more accurate than before.