Microwave Interference Effects on Devices: Recent Progress Presentation

1. Microwave Interference Effects on Device, Integrated Circuits and PC-Board System A Presentation on Recent Progress N. Goldsman, Y. Bai, A. Akturk, T. Chitnis, B. Jacob, J. Baker, A. Iliadis, J. Melngailis 10/10/01 • Effects on PC-Board and System Level • Effects on Integrated Circuit Level • Effects on Device Level

2. Standard Planar Technology Implementation:IC Chips on PC Board Chip-to-Chip Connection on PC Board: PC Board Bond Pad Die (Integrated Circuits) Input Output Pins Bond Wire Transmission Line

3. Chip-to-Chip Connection Bond Wire Bond Pad Pins Input Output ICs ICs Transmission Line

4. Bond Pad Die (Integrated Circuits) Electro-Static Discharge (ESD) IC Chip with Bond Pads

5. Metal Insulator Oxide Si Substrate Bond Pad Bond Wire Close Shot of Bond Pad Bonding Wire

6. Classification of Bond Pads • Analog Reference Pad • Bi-Directional Pad with Buffer • Ground Pad • Input Pad with Buffer • I/O Pad • Padless Corner Pad • Padless Spacer Pad • Pad No Connect Pad • Output Pad with Buffer • Power Pad

7. Bond Pad ESD Transistor PMOS Pad Logic ESD Transistor NMOS ESD Pad --- Eliminate Harmful Static Charge Example I/O ESD Pad: Schematic Layout

8. Metal Insulator Oxide Si Substrate Metal Layer Substrate Bond Pad Parasitics - Capacitance Pad Parasitic Capacitance vs. Process (Ref: MOSIS) Plate Capacitor

9. IC Package Bond Pad Bond Wire Pin Bond Wire & Pin (Several nano-Henry) Die Bond Pad Bond Pad (Several Hundred femto-Farad) Bond Wire Pin Effects of Bond Pad Parasitics on Circuit Performance --- Matching Package Parasitics

10. Effects of Bond Pad Parasitics on Circuit Performance --- Matching Chip-to-Chip Connection on PC Board Transmission Line Bond Wire Bond Pad Pins

11. IC 1 IC 2 Input Output Transmission Line Effects of Bond Pad Parasitics on Circuit Performance --- Matching Input Output IC 1 IC 2

12. Effects of Bond Pad Parasitics on Circuit Performance --- Matching • Why to Match? • Maximize Power Transformation • Eliminate Reflection Match impedance on board with bond pads, bond wire and pins: IC 1 IC 2 Input Output Transmission Line Tune to Z0 Tune to Z0 Tune to Z0 Z0 If Impedances are not matched, signals will get reflected.

13. CMOS Low Noise AmplifierIC1 Input Circuit • Inductor L1 and capacitors C1 and C2 are on – chip components for input matching. • Inductor L2 is the downbond inductor and is also used in input matching. • In addition to the shown components the pad capacitance and package model were taken into consideration.

14. Matching • Looking into the MOSFET M1, input impedance • The real part is made to be 50 Ohms. • Inductors L1 and C1 give additional degrees of freedom to have the input resonate at 2.4 GHz • Values are tuned to include effects of pad and package parasitics • Models provided by the foundry were used for on-chip inductors and capacitors. Real part

15. Transistor sizing • Sizing is an important factor in the Power consumed vs. Noise Figure trade off. The expression below is derived by constraining the power consumed and then optimizing the Noise Figure. • Substituting appropriate values gives a transistor size of W = 200 microns.  = Operating frequency L = Device Length Rs = Source Resistance

16. CMOS LNA Layout Input_C1 Input_L1 MOSFETs Output_C2

17. Simulation Results • Simulation results • Operating at 2.4 GHz • Power gain = 21 dB • Noise Figure = 2.7 dB • Supply voltage = 2.5V • Idc = 7.5 mA This is a test chip. Results are obtained for an output termination of 50 Ohms

18. Effects of Bond Pad Parasitics on Circuit Performance --- Matching Example Circuit: RF Power Amplifier Bond Pad, Bond Wire, and Pin Bond Pad, Bond Wire, and Pin PA without bond pads or package parasitics PA with bond pads and package parasitics Bond pad, bond wire, and pin add together which shift the resonant frequency, decrease the power gain, and narrow the bandwidth of the amplifier.

19. Device Switching Details Performance Improves by • the reduction of the capacitive load • the utilization of the halo implants

20. General Device Hierarchy => => =>

21. Governing Equations <= Device Equations are solved for each mesh point / <= \ Supplementary device equations => => Supplementary Lumped circuit equation

22. Example Solutions of the Previous Equations • Potential Distribution: • The applied voltage at the gate is shared between the oxide and the • surface after the built-in voltages are deducted. • More electrons are attracted to the channel as VGS gets higher. This also drags the surface potential to a higher level • As the gate voltage increases, the surface potential does not increase linearly, causing the vertical electrical field to take higher values. This might eventually lead to a breakdown, around 3MV/cm Carrier Distribution: • To turn the device on, the minority carriers are attracted to the oxide interface, ultimately they invert the surface and form a conductive channel, • by the application of a positive VGS for electrons and negative for holes • When the device is turned on, the accumulation of the carriers at the interface forms the conductive path

23. Potential Distribution for VGS=1V and VGS=5V VDS=1.5V and VSB=0V VGS=1V EOX_MAX=3MV/cm VGS=5V EOX_MAX=15MV/cm

24. Electron Concentration of NMOS throughout the substrate, specifically around the interface, when the channel is on and off Off On The bump shows the attracted carriers

25. Hole Concentration of PMOS throughout the substrate, specifically around the interface, when the channel is on and off On Off The bump shows the attracted carriers