SILICON-ON-INSULATOR MESFETs AT THE 45nm NODE

Abstract

Metal-semiconductor field-effect-transistors (MESFETs) have been fabricated using a commercially available 45nm silicon-on-insulator (SOI) CMOS foundry with no changes to the process flow. Depending upon the layout dimensions, these n-channel, depletion mode devices can be designed for high current drive (ID SAT ≥ 100mA/mm), high operating frequency ( fmax >35 GHz) or enhanced breakdown voltage (VBD >25V). The design flexibility provided by the SOI MESFETs, coupled with the high performance of ULSI CMOS at the 45nm node will enable a variety of analog, RF and mixed signal applications.

Impact Ionization in SOI MESFETs at the 32-nm Node

“…Without the need for a fragile gate oxide, the breakdown voltage, V BD , of the MESFETs exceeds that of the baseline CMOS devices. Breakdown voltages in excess of 12 and 25 V have been demonstrated at the 150- [13] and 45-nm nodes [14], respectively. At drain voltages higher than V BD , the saturated drain current rapidly increases due to avalanche breakdown as described in [16].…”

“…While the transport properties of silicon are not as favorable as those of compound semiconductors, such as GaAs and GaN, the promise of low-cost integration with highly scaled CMOS offers a number of advantages for mixed-signal and system-on-a-chip applications. Enhanced voltage silicon MESFETs have been demonstrated using commercially available silicon-on-insulator (SOI) CMOS technologies at the 350 [12], 150 [13], and 45 nm [14], [15] CMOS nodes. Without the need for a fragile gate oxide, the breakdown voltage, V BD , of the MESFETs exceeds that of the baseline CMOS devices.…”