High performance wafer scale flexible InP double heterogeneous bipolar transistors

Abstract

This letter reports on the first demonstration of wafer scale flexible InP double heterogeneous bipolar transistors (DHBTs) with record cut-off frequency (f T) and maximum oscillation frequency (f MAX). The as-fabricated DHBTs on 3-inch InP bulk substrate are separated by epitaxial layer lift-off, followed by adhesive bonding onto flexible substrate. Radio frequency measurements reveal that the InP DHBTs on flexible substrate exhibit a f T of 337 GHz and f MAX of 485 GHz, representing the highest f T and f MAX ever reported in flexible electronics. Moreover, InP DHBTs on flexible substrate have good consistency and the functional transistor yield is more than 73%. The results provide ways to accelerate the time for flexible electronics toward future applications working at multi-gigahertz range.

RF characterization of InP double heterojunction bipolar transistors on a flexible substrate under bending conditions

“…Using extrapolation of U and |h 21 | 2 with a -20 dB/dec roll-off yields method, which shows the cut off frequency f T = 395 GHz, the maximum oscillation frequency f MAX = 630 GHz The RF performance f T and f MAX of the flexible substrate InP DHBT device in this paper are compared with the performance of other flexible transistors reported previously in Refs. [13,15,17,18,[24][25][26][27], as shown in Table 1. Our work shows the highest RF frequency performance of flexible devices to date, besides confirms the potential of flexible substrate InP DHBT for high frequency applications.…”