The Effect of Spacer Thicknesses on Si-Based Resonant Interband Tunneling Diode Performance and Their Application to Low-Power Tunneling Diode SRAM Circuits

Si-based resonant interband tunneling diodes (RITD) with spacer thicknesses varying from 1 to 16 nm were grown and fabricated. The effect of spacer thickness on the peak-to-valley current ratio (PVCR), peak current density Jp, and voltage swing was studied. By increasing the tunneling spacer thickness up to 16 nm, RITDs with a J p of as low as 20 mA/cm2 with an associated PVCR of 1.6 were obtained, which are suitable for low-power tunnel diode SRAM applications. With the previously reported highest RITD Jp of 218 kA/cm2, a Jp spanning nearly seven orders of magnitude can be obtained by engineering the tunneling spacer thickness and doping densities, thus demonstrating tremendous flexibility to optimize Jp for different circuit applications (logic, memory, and mixed-signal). Using a low-current-density RITD developed in this paper, a bread-boarded one-transistor tunneling-based SRAM (TSRAM) memory cell with low standby power consumption was demonstrated. This is the first report of a Si-based TSRAM memory circuit using Si-based RITDs. The result demonstrates the potential of Si-based tunnel diodes for low-power memory applications

[1]  Paul R. Berger,et al.  pnp Si resonant interband tunnel diode with symmetrical NDR , 2001 .

[2]  P.R. Berger,et al.  Si/SiGe resonant interband tunnel diode with f/sub r0/ 20.2 GHz and peak current density 218 kA/cm/sup 2/ for K-band mixed-signal applications , 2006, IEEE Electron Device Letters.

[3]  Santosh K. Kurinec,et al.  Diffusion barrier cladding in Si/SiGe resonant interband tunneling diodes and their patterned growth on PMOS source/drain regions , 2003 .

[4]  P.R. Berger,et al.  Tri-state logic using vertically integrated Si-SiGe resonant interband tunneling diodes with double NDR , 2004, IEEE Electron Device Letters.

[5]  Gerhard Klimeck,et al.  Room temperature operation of epitaxially grown Si/Si0.5Ge0.5/Si resonant interband tunneling diodes , 1998 .

[6]  J.P.A. van der Wagt,et al.  RTD/HFET low standby power SRAM gain cell , 1998, IEEE Electron Device Letters.

[7]  U. Smith,et al.  Long-term stability and electrical properties of compensation doped poly-Si IC-resistors , 2000 .

[8]  Eiiti Wada,et al.  Esaki Diode High-Speed Logical Circuits , 1960, IRE Trans. Electron. Comput..

[9]  Paul R. Berger,et al.  Monolithically integrated Si/SiGe resonant interband tunnel diode/CMOS demonstrating low voltage MOBILE operation , 2004 .

[10]  J.P.A. van der Wagt,et al.  Tunneling-based SRAM , 1999, Proc. IEEE.

[11]  R. A. Logan,et al.  Excess Tunnel Current in Silicon Esaki Junctions , 1961 .

[12]  B. Brar,et al.  A monolithic 4 bit 2 GSps resonant tunneling analog-to-digital converter , 1997, GaAs IC Symposium. IEEE Gallium Arsenide Integrated Circuit Symposium. 19th Annual Technical Digest 1997.

[13]  Paul R. Berger,et al.  Si resonant interband tunnel diodes grown by low-temperature molecular-beam epitaxy , 1999 .

[14]  Paul R. Berger,et al.  Monolithically integrated Si/SiGe resonant interband tunneling diodes/CMOS MOBILE latch with high voltage swing , 2003, International Semiconductor Device Research Symposium, 2003.

[15]  A. Seabaugh,et al.  RTD/HFET low standby power SRAM gain cell , 1996, International Electron Devices Meeting. Technical Digest.

[16]  Paul R. Berger,et al.  Three-terminal Si-based negative differential resistance circuit element with adjustable peak-to-valley current ratios using a monolithic vertical integration , 2004 .

[17]  J.P.A. van der Wagt,et al.  Tunnelling-based SRAM , 1999 .

[18]  Paul R. Berger,et al.  151 kA/cm2 peak current densities in Si/SiGe resonant interband tunneling diodes for high-power mixed-signal applications , 2003 .

[19]  Paul R. Berger,et al.  Growth temperature and dopant species effects on deep levels in Si grown by low temperature molecular beam epitaxy , 2003 .

[20]  H.J. De Los Santos,et al.  An efficient HBT/RTD oscillator for wireless applications , 2001, IEEE Microwave and Wireless Components Letters.

[21]  Paul R. Berger,et al.  Annealing of defect density and excess currents in Si-based tunnel diodes grown by low-temperature molecular-beam epitaxy , 2004 .

[22]  K. Eberl,et al.  Physics and applications of Si/SiGe/Si resonant interband tunneling diodes , 2000 .

[23]  R. Yu,et al.  NMOS/SiGe Resonant Interband Tunneling Diode Static Random Access Memory , 2006, 2006 64th Device Research Conference.