A high-power and high-gain X-band Si/SiGe/Si heterojunction bipolar transistor

Abstract

A double mesa-type Si/SiGe/Si (n-p-n) heterojunction bipolar transistor (HBT) with record output power and power gain at-band (8.4 GHz) is demonstrated. The device exhibits collector breakdown voltage BV CBO of more than 24 V and a maximum oscillation frequency max of 37 GHz. Under continuous-wave operation and class-AB biasing conditions, 24.2-dBm (263-mW) RF output power with concurrent gain of 6.9 dB is measured at the peak power-added efficiency (28.1%) from a single ten-emitter fingers (780-m 2 emitter area) common-base HBT. The maximum RF output power achieved is as high as 26.3 dBm (430 mW in saturation) and the maximum collector efficiency is 36.9%. The low collector doping concentration together with the device layout result in negligible thermal effects across the transistor and greatly simplifies the large-signal modeling. The conventional Gummel-Poon model yields good agreement between the modeled and the measured dc characteristics and small-signal-parameters. The accuracy of the model is further validated with the measured power performance of the SiGe power HBT at-band. These results set a benchmark for power performance for SiGe-based HBTs and indicate promise for their implementation in efficient-band poweramplifier circuits.

Superiority of common-base to common-emitter heterojunction bipolar transistors

“…Consequently, if the extrinsic base resistance ͑thus the total base resistance͒ of an HBT is also made sufficiently small, the power gain superiority of CB configuration can then always be notable. [4][5][6] The major applications of HBTs are high-speed driving and radio-frequency ͑rf͒ power amplification ͑e.g., optical fiber communications and GaAs and SiGe HBTs used in majority of cell phone rf power amplifiers͒. For these applications, large-signal power handling capability of HBTs ͑with associated power gain and power-added efficiency͒ is the most important performance parameter of concern.…”

High performance SiGe HBT power unit-cell for S-Band open collector adaptive bias power amplifier design

“…Three NPN transistor types are offered in this process; a high speed NPN (BV CEO = 2.5 V, peak F t around 67 GHz at V CE = 1 V), a standard NPN (BV CEO = 3.8 V, peak F t around 49 GHz at V CE = 1 V), and a high voltage NPN (BV CEO = 6 V, peak F t around 27 GHz at V CE = 1 V). In actual device fabrication process, a high breakdown voltage with a lower current density is preferred for HBT power device design [10]. In this work, a single finger high voltage NPN with an emitter area of 0.9 · 13.9 lm 2 was fabricated for the HBT power device, including deep trench-isolation, three metal layers, resistors, varactors, metal-insulator-metal (MIM) capacitors and variable inductors for a wide variety of analog, mixed-signal and RF applications.…”

Linearity and Power Characteristics of SiGe HBTs at High Temperatures for RF Applications

“…A challenge faced by SiGe-based power amplifier technologies is providing sufficient high-voltage immunity without compromising power performance. By optimizing the SiGe process, the microwave power applications of SiGe-based HBT under investigation and development have moved from L-, S-, and C-band operations [5], [6] to X-band operation [7].…”