以基因演算法改善高電子遷移率電晶體高頻參數之萃取精準度

1. 2007 CIEE 中部院校大專生專題競賽口試報告 Intrinsic Extrinsic Ri (Ω) 26.585 Lg (nH) 0.0236 Rds (Ω) 1310.05 Ld (nH) 0.0811 Gm (mS) 11.039 Ls (nH) 0.1118 T (ps) 0.4976 Rg (Ω) 13.1677 Cgd (pF) 0.0126 Rd (Ω) 25.2 Cgs (pF) 0.1478 Rs (Ω) 4.9429 Cds (pF) 0.0029 Cpg (pF) 0.00575 Cpd (pF) 0.0394 以基因演算法改善高電子遷移率電晶體高頻參數之萃取精準度 Improved Parametric Extraction and High-Frequency Model Build-Up for HEMT by using Genetic Algorithms 陳珮琳 逢甲大學電子工程系 Abstract This work reports an accurate, reliable, and systematic method to extract the small-signal equivalent-circuit elements of the high electron mobility transistor (HEMT) models by integrating the Generic algorithm (GA) analyses. Superior extraction accuracy of 95% over the entire operation frequency range has been achieved. Different from the strong dependence on the starting value of parameter search by the conventional techniques, the proposed method sets the respective searching range with physical meanings by referring to the initial values. The proposed methodology can be applied to extracting different high-speed devices and is promisingly useful for the RFIC design technologies. . Source Drain Gate Rs Rd Rg Cap Layer Cgd Cgs Schottky Layer Ri gmVe-jwτ Channel rds Substrate Cds • Fig. 1. Small-signal model of HEMT. Measured S Parameters Fig. 3. Comparisonsof real-part S-parameter values. Genetic Algorithm : Encode Genetic Algorithm : Randomly producing the initial population Error Fitness Function Small Signal Model Set up the Range of The Parameters S11 S12 S21 S22 Genetic Algorithm : Decode No Genetic Algorithm : Reproduction Crossover Mutation Yes Meet the end conditions? Generation=1000 Fig. 2. The Genetic algorithmflowchart. Fig. 4. Comparisonsof imaginary-part S-parameter values. • Table 1. Extracted physically meaningful small-signal parameters. • Conclusion • In summary, an accurate and reliable device extraction methodology by using the Generic algorithms to determine the small-signal equivalent-circuit elements of HEMT models has been successfully proposed. Superior extraction precision of 95% in average over the entire operation frequency range has been accomplished. The present method can successfully resolve the extraction inaccuracy in the analytical methods or the ambiguity and lack of physical meanings in the conventional methods. It can be easily modified to extract different high-speed device structures. This work is beneficial to the device characterization and MMIC • design applications. • Fig. 5. Fig. 5. Comparisons of high-frequency characteristics.