1. NEW ANALYTIC DC MODELS FOR TUNNEL DIODE AND RESONANT TUNNELING DIODE Chien M. Ta (SMA) Fujiang Lin (IME) Subhash R. Chander (IME) SYMPOSIUM ON ELECTRONICS June 2004

2. June 04, 2004Symposium on Electronics 20042 Outline Introduction Literature reviews Approach and tools Achievements Remarks and discussions

3. June 04, 2004Symposium on Electronics 20043 Introduction Motivations –UWB system design –Currently, no RTD’s model in commercial EDA tools Objectives –Analytic expressions for the I-V characteristic curves of TD and RTD

4. June 04, 2004Symposium on Electronics 20044 Reviews Existing models – Piecewise linear model (Tai-Haur Kuo et al., Ralph P. Santoro) – Polynomial fit model (M. R. Deshpande et al.) – Gaussian-exponential combination (Zhixin Yan and M.J.Deen) – Physics-based model (J. N. Schulman et al.) I-V characteristic What are the interesting features of tunnel diode and resonant tunneling diode? Negative differential resistance (NDR) Fast Temperature insensitivity

5. June 04, 2004Symposium on Electronics 20045 Modeling Analytical approach Tools: MATLAB, IC-CAP

6. June 04, 2004Symposium on Electronics 20046 Methodology I-V characteristic measurement Mathematic analysis Model proposal Simulation Compare Final model Satisfactory match Unsatisfactory match

7. June 04, 2004Symposium on Electronics 20047 TD modeling - Measurement IC-CAP setup for measuring I-V characteristic Measured I-V characteristic

8. June 04, 2004Symposium on Electronics 20048 Analytic model where I s_rev n rev IpVpAIpVpA I s_fwd n fwd I-V characteristic

9. June 04, 2004Symposium on Electronics 20049 Simulation ParameterExtracted valueOptimized value I s_rev 95.21 x 10 -6 525 x 10 -6 n rev 1.0013.011 I s_fwd 90.51 x 10 -6 73.16 x 10 -6 n fwd 7.0216.339 VpVp 80 x 10 -3 40.57 x 10 -3 IpIp 372.3 x 10 -6 494.5 x 10 -6 A1013.83 Final RMS error = 0.95% Maximum error = 2.28% I-V characteristic with extracted valuesI-V characteristic with optimized values

10. June 04, 2004Symposium on Electronics 200410 New model for resonant tunneling diode where I-V characteristic ISnISn AA

11. June 04, 2004Symposium on Electronics 200411 Simulation ParameterOptimized values A652.7x10 -9  2.719  16.92  2.593 ISIS 2.2248x10 -19 n0.7882 Final RMS error = 3.813% Simulation result

12. June 04, 2004Symposium on Electronics 200412 Symmetric characteristics for RTD where Simulation result Symmetric I-V characteristic

13. June 04, 2004Symposium on Electronics 200413 One model for both TD and RTD ? ParameterOptimized values A831.3x10 -6  0.2883  1.091  16.67 ISIS 108.9x10 -6 n7.146 Final RMS error = 1.03% Recognizable deviation in the reverse-biased region (not very critical since the devices are usually biased in the NDR region) Not much degradation compared to 0.95% RMS error of the TD’s model

14. June 04, 2004Symposium on Electronics 200414 Remarks, conclusion, and future works Remarks –Excellent match between simulation and measurement: RMS error is less than 1% for TD and 3.8% for RTD –Need accurate measurement, especially for ac modeling: de-embedding technique –Need modification to have scalability Conclusion –The new DC model for the RTD is sufficient to describe the behaviors of the devices Future works –AC model expansion –Implementation into EDA tools –Coding in Verilog-A

15. June 04, 2004Symposium on Electronics 200415 THANK YOU