C. Monier

Observation of enhanced transport in carbon-doped InGaAsN after in situ anneal and its impact on performance of NpN InGaP/InGaAsN heterojunction bipolar transistors

The incorporation of a low band gap carbon-doped InGaAsN material into a standard GaAs heterojunction bipolar transistor (HBT) has great potential to achieve higher operating efficiency at lower bias conditions. In order to improve the performance of the initial as-grown InGaAsN-based HBTs (with 1% N and 3% In for an energy band gap EG of 1.2 eV), the effects of different thermal treatments on material quality and their impact on dc and rf characteristics on small-area devices are examined in this letter. A degradation of the base transport is observed after a postgrowth anneal associated with lower current gain β and degraded microwave properties. An in situ anneal approach under inert ambient conducted following the emitter growth, increases the active doping level (with a base sheet resistance RSH three times lower than the as-grown structure and demonstrates suitable high frequency performance for a device with such a large amount of nitrogen in the base.

Significant operating voltage reduction on high-speed GaAs-based heterojunction bipolar transistors using a low band gap InGaAsN base layer

We report the fabrication of double heterojunction bipolar transistors (DHBTs) with the use of a new quaternary InGaAsN material system that takes advantage of a low-energy band gap E/sub G/ in the base to reduce operating voltages in GaAs-based electronic devices. InGaP/In/sub 0.03/Ga/sub 0.97/As/sub 0.99/N/sub 0.01//GaAs DHBTs with improved band gap engineering at both heterojunctions exhibit a DC peak current gain over 16 with small active emitter area. The use of the lattice-matched In/sub 0.03/Ga/sub 0.97/As/sub 0.99/N/sub 0.01/ (E/sub G/=1.20 eV) base layer allows a significant reduction of the turn-on voltage by 250 mV over standard InGaP/GaAs HBTs, while attaining good high-frequency characteristics with cutoff frequency and maximum oscillation frequency as high as 40 GHz and 72 GHz, respectively. Despite inherent transport limitations at the present time, which penalize peak frequencies, this novel technology provides comparable RF performance to conventional devices with a GaAs control base layer but at much lower operating base-emitter bias conditions. This technical progress should benefit to the next generation of RF circuits using GaAs-based HBTs with lower power consumption and better handling of supply voltages in battery-operated wireless handsets.

High-speed InGaP/InGaAsN/GaAs NpN double heterojunction bipolar transistors with low turn-on voltage

Abstract A current gain β of 23 is demonstrated from a small-area NpN GaAs-based double heterojunction bipolar transistor (HBT) using a low band-gap InGaAsN material (lattice matched to GaAs with an energy band gap EG of 1.2 eV) as the base layer. An improved band-gap engineering design at both emitter–base and base–collector heterojunctions in this GaAs-based HBT structure allows significant turn-on voltage reduction up to 270 mV compared to conventional InGaP/GaAs HBTs, while attaining high-speed performance. Self-aligned devices with emitter active area of 3×5 μm2 show cutoff frequency fT and maximum oscillation frequency fMAX values of 32 and 52 GHz, respectively. These results demonstrate the strong potential of this novel HBT technology to reduce power consumption in future wireless handsets using the GaAs manufacturing platform.

High-speed performance of NpN InGaAsN-based double heterojunction bipolar transistors

We report the fabrication of double heterojunction bipolar transistors (DHBTs) with the use of a new quaternary InGaAsN material system that takes advantage of a low energy band gap in the base to reduce operating voltages in GaAs-based electronic devices. InGaP/In/sub 0.03/Ga/sub 0.97/As/sub 0.99/N/sub 0.01//GaAs DHBTs with improved band gap engineering at both heterojunctions exhibit a DC peak current gain over 16 with small active emitter area. The use of the InGaAsN base layer allows a significant reduction of the turn-on voltage by 250 mV for the new technology over a standard InGaP/GaAs HBT, while maintaining high-frequency characteristics with cut-off frequency and maximum oscillation frequency as high as 40 GHz and 70 GHz, respectively. This technology is promising for next generation RF circuits using GaAs-based HBTs by reducing the operating voltage for low power consumption and better handling of supply voltages in advanced wireless handsets.

NpN InGaAsN-based heterojunction bipolar transistors with f/sub max/ = 60 GHz

Microwave measurements from 3x5 /spl mu/m/sup 2/ self-aligned NpN InGaAsN DHBT devices indicate that this low band gap material system can be successfully implemented in a GaAs-based HBT structure for lowering the turn-on voltage while attaining high-speed performance.

First demonstration of the AlGaAs-InGaAsN-GaAs P-n-P double heterojunction bipolar transistor

InGaAsN has received a lot of attention lately. Incorporating a small amount of nitrogen (N) into InGaAs reduces the strain of InGaAs layer grown on GaAs (Sakai et al, 1993; Van Vechten, 1969). In addition, the E/sub G/ decreases as N is added, which is a desirable characteristic for GaAs-based device structures that require material with a smaller E/sub G/ than the 1.42 eV of GaAs. A heterojunction bipolar transistor (HBT) for low-power applications could also take advantage of the smaller E/sub G/ of InGaAsN for reduction of its turn-on voltage (V/sub ON/), and because InGaAsN is lattice matched to GaAs, the resulting device is compatible with existing GaAs foundries. The first functional InGaAsN N-p-N double heterojunction bipolar transistor (DHBT) was demonstrated recently with reduced V/sub ON/ (Chang et al, 2000). The complementary heterojunction bipolar transistor (CHBT) technology has the potential for enhanced circuit performance for digital, analog, and microwave applications compared to circuits using only N-p-n HBTs (Sawdi and Pavlidis, 1999). The goal of this study is to optimize the P-n-p InGaAsN HBT. Realization of the P-n-p InGaAsN HBT, in conjunction with the N-p-n InGaAsN HBT technology, would allow the advantages of the CHBT technology to further extend the usefulness of the InGaAsN-based low-power electronics.