Elevated temperature performance of pseudomorphic AlGaAs/InGaAs MODFETs

The use of δ-doping in HFET processes has made the development of transistor circuits and logic gates possible, for very high-frequency/speed or low-power applications. This behaviour of the PHFET device is due to fast quantum well conduction. However, the effect of the operating temperature range is critical. This range depends on the transistor and circuit activity, the packaging technique, and the external operating conditions. Temperature strongly affects the device ability to confine the current flow into the quantum well channel. In this paper the effect of temperature and δ-doping concentration on the performance of the device is investigated by means of simulated experiments. The results are analytically and qualitatively discussed, showing how to fine tune the δ-doping concentration in order to optimize the P-HFET behaviour from medium-to high-temperature conditions, [300, 500] K.

Section: The Simulated P-hfetmentioning

confidence: 99%

Section: The Simulator Modelling Considerationsmentioning

confidence: 99%

Optimization of the delta-doped layer in P-HFETs at medium/high temperatures

González¹,

Hernández²,

Garcı́a³

et al. 2000

“…As a result, a great number of applications in microwave monolithic integrated circuits (MMICs) are based on this transistor [2,3]. Typical temperatures of operation are moderate, from 300 to 400 K. Nevertheless, device characteristics of MODFETs may significantly change in this range [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Normally, the extrinsic resistances are measured at different temperatures in linear region, assuming that in saturation their values are preserved [5,8]. Thus, sometimes they are assumed equal when modelled [5,9], or the barriers are characterized by a specific barrier resistivity dominated by thermionic field emission [10].…”

Section: Introductionmentioning

confidence: 99%

Characterization of extrinsic resistances in temperature behaviour modelling of InGaAs MODFETs

González¹,

Hernández²,

Garcı́a³

et al. 2004

This work analyses the dc response of InGaAs channel modulation-doped field-effect transistors, when varying temperature from 300 to 400 K. An analytical model for the intrinsic drain current is derived from previous work, carried out for a similar AlGaAs channel device, in order to show explicitly the temperature dependence. The extrinsic resistances are numerically evaluated and added in a straightforward form to the model. Experimental output characteristics at different temperatures of an InGaAs MODFET, in static operation, are compared with those offered by the resulting extrinsic model and numerical simulations. Computed relative errors are around 10%.

“…As far as we know, there are few publications regarding HFET simulations at different temperatures. Zurek et al [6] consider temperature variations, but simulations only include the intrinsic device, as pointed out above. Local self-heating effects in short gate HFETs are studied in [7], but once again, the extrinsic resistances had to be measured.…”

Section: Introductionmentioning

confidence: 99%

Static simulation of pseudomorphic heterostructure FETs at medium/high temperatures

González

Hernández

González‐Sanz

et al. 2002

The drain current in a pseudomorphic heterostructure FET (P-HFET) has a negative temperature dependence which is correctly predicted when the electron transport through the barriers is taken into account. In order to compare simulation with experimental results, the static output characteristics on a long gate P-HFET have been measured over the temperature range 260-380 K. Hall mobility measurements at different temperatures and gate bias are included in the simulations. The static characteristics are simulated using a thermionic field emission model that calculates the current across the Al 0.3 Ga 0.7 As/In 0.3 Ga 0.7 As heterojunction, where the effective band discontinuity is controlled by means of a parameter called effective length, l ef . In this paper the use of l ef as a fitting parameter for the static characteristic curves is investigated.