Delta-doped complementary heterostructure FETs with high Y-value pseudomorphic In/sub 1/Ga/sub 1-y/As channels for ultra-low-power digital IC applications

Abstract

We report on the device and circuit performance of Delta-Doped Complementary Heterostructure Insulated Gate Field Effect Transistors (C-HIGFETs) which make use of a high lnAs mole fraction (y-value) pseudomorphic InyGal-yAs channel along with a subchannel deltadoped Si layer to adjust the n-HIGFET and p-HIGFET threshold voltages. Results are presented showing that increasing the y-value of the In Gal. As channel up to y = 0.25 enhances both the n-hGFl!T and the p-HIGFET device performance as evidenced by the high transconductance values (i.e., Gmn >300 mS/mm and Gmp >70 mS/mm respectively) for 1pm gate length devices. We present results from lnyGal-YAs channel (y-0.25) C-HIGFET ring oscillators with less than 4 pW/gate standby-power consumption.These C-HIGFET ring oscillators exhibit gate delays as low as 143 psec at a standby-power of 40 pW/gate and a switching-power-delay product of 250 fJ. We also report on the first fully functional Delta-Doped C-HIGFET 1K X 4 SRAM operating at a 284 MHz clock frequency and consuming only 183 mW.introduction

0.7 micron gate length complementary Al/sub 0.75/Ga/sub 0.25/As/In/sub 0.25/Ga/sub 0.75/As/GaAs HIGFET technology for high speed/low power digital circuits

“…Previous studies of 1 pm gate length C-HIGFET devices and circuits have explored the dependence of the performance of these devices and circuits on the doping profile beneath the InGaAs channel and on the composition of the AIGaAs gate barrier (1)(2)(3)(4)(5). It hais been shown that a planar ndoped layer in the GaAs buffer region below the lnyGal-yAs channel can adjust the threshold voltages of n-and p-channel devices anld that it tends to reduce subthreshold leakage and output conductance of the p-channel device thus giving it much improved operating characteristics.…”