GaAs MESFET interface considerations

Wager, John F.; McCamant, A.J.

doi:10.1109/t-ed.1987.23036

Cited by 46 publications

(6 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The LT GaAs MISFET shows insensitivity to the light, giving no significant shift of threshold voltage V th under illumination. This is in contrast to the large shift of V th normally seen in conventional GaAs FETs [12], where the shift of V th is known to be related to the high density of defect states whereby the incidence of illumination would release the trapped electrons and cause a shift of V th . The charging and discharging of surface states also cause hysteresis of drainsource current [12], but with the formation of the as-grown LT GaAs layer the surface states are effectively passivated.…”

Section: DC Characteristicsmentioning

confidence: 60%

Low-temperature grown GaAs insulators for GaAs FET applications

Thomas

Luo

Morgan

et al. 1996

Semicond. Sci. Technol.

View full text Add to dashboard Cite

Low-temperature (LT) grown GaAs in either an as-grown or annealed condition has been used as a gate dielectric for GaAs field effect transistors (FET). It was found that both types of LT GaAs layers can effectively passivate the device surface states, eliminate hysteresis and light induced effects, and dramatically increase the breakdown voltage, V BD , between source and drain contacts of the FETs. V BD was found to increase on cooling the as-grown LT GaAs FET with a low activation energy, typically ∼ 0.15 eV for the corresponding reverse bias gate current. However, for the annealed LT GaAs FET, V BD decreased with decreasing temperature and the fixed reverse bias gate current showed a large activation energy ∼ 0.5 eV. A large gate-lag and kink effect was observed from the annealed LT GaAs FETs, but was insignificant for the as-grown LT GaAs FETs. The superior performance of the as-grown LT GaAs FETs is attributed to the high degree of hopping conductivity found, and the high breakdown characteristic of the as-grown LT GaAs. The high density of defects and the trap-like nature of the As/GaAs clusters in annealed LT GaAs layer are believed to be responsible for the transient behaviour and large values of activation energy found in the annealed LT GaAs FETs.

show abstract

Section: DC Characteristicsmentioning

confidence: 60%

Low-temperature grown GaAs insulators for GaAs FET applications

Thomas

Luo

Morgan

et al. 1996

Semicond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The observed hysteresis can be interpreted as a result of the junction between substrate and channel related to EL 2 traps whose roles have been recognized in the studies of the sidegating effect [6][7][8][9]. The space-charge distribution of the C-S junction resembles a p-n junction with depletion region located in doped channel and formed by the charge of ionized donors.…”

Section: Resultsmentioning

confidence: 92%

Effects of channel-substrate interface on hysteresis of sidegating effect in GaAs MESFETs

Ding

Yan

2010

Chin. Sci. Bull.

View full text Add to dashboard Cite

With sidegating bias, hysteresis of sidegating effect is usually observed in drain current. The experimental results presented in this letter demonstrate that the hysteresis with time-based characteristics is closely related to EL 2 traps and channel-substrate (C-S) junction peculiarities. The response of depletion region of C-S junction to the electron capture and emission by trap-EL 2 plays an important role in the hysteresis. Furthermore, a new mechanism is proposed to explain the time-based characteristics of hysteresis, i.e., there is a "steady-state" in which the hysteresis disappears. GaAs MESFET, sidegating bias, hysteresis, channel-substrate interface Citation:Ding Y,Yan X L. Effects of channel-substrate interface on hysteresis of sidegating effect in GaAs MESFETs.MESFET is considered as one of the important devices for the applications of high power, high frequency and high efficiency RF&MW electric circuit [1]. However, the demand for higher speeds and increased functionality in circuits using GaAs MESFETs has led to a continual reduction in dimensions and an increase in circuit density. Higher density has led to increased sensitivity to sidegating effect, and requires careful layout design rules. In particular, these devices can exhibit an abrupt decrease in drain current at high voltage across the electrode which is set near the MESFET, known as sidegating effect [2]. In this paper, the hysteresis of sidegating effect is investigated, and it is proposed that this is due to the channel-substrate interface. Hysteresis is usually observed in drain current (I DS ) as a function of negative sidegate bias voltage (V SG ) when measuring the threshold behavior of sidegating effect [2,3] in GaAs MESFETs on the voltage-controlled condition [4,5]. When V SG varies positively or negatively, I DS follows different paths and shows apparent hysteresis. This phenomenon has been attributed to the S-type negative differential conductivity of the substrate [4] and the Schottky *Corresponding author (email: dingy@vlsi.zju.edu.cn) contact to the substrate [5]. However, experimental results presented in this letter demonstrate that the response of channel-substrate junction's depletion region to the electron capture and emission by trap-EL 2 plays an important role in the hysteresis. Furthermore, a so-called "steady-state" exists where the hysteresis disappears. This phenomenon disagrees with previous reports.

show abstract

Section: Citationmentioning

confidence: 99%

“…Chinese Sci Bull, 2011Bull, , 56: 1267Bull, −1271Bull, , doi: 10.1007 MESFET is considered as one of the important devices for the applications of high power, high frequency and high efficiency microwave electric circuit [1,2]. However, as the demand for higher speeds and increased functionality in circuits, low-frequency noises (LFN) in currents, such as thermal noise, 1/f noise, generation-recombination noise, diffusion noise and shot noise, in various GaAs FET structures have been reported [3][4][5][6][7][8][9][10]. The main characteristics of these noises are: (1) LFN strongly depends upon the substrate materials.…”

mentioning

confidence: 99%

“…Miller and Bujatti attributed LFN directly to the oscillations in leakage currents in the semi-insulating (SI) GaAs substrate [5]. While Wager pointed out that LFN in channel current could not be simply attributed to the oscillations in leakage current of the substrate, but related to the peculiarities of channel-substrate junction [9].In this paper, LFN in MESFET's currents is investigated under sidegating conditions, and the mechanism is identified whereby the current fluctuation is directly related to the sidegate bias. Unlike Birbas's explanation in terms of an unreal negative capacitance of the depletion region in buffer-channel interface [11], we associate LFN with the substrate conductivity and channel-substrate junction modulated by sidegate bias.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Low-frequency noises in GaAs MESFET’s currents associated with substrate conductivity and channel-substrate junction

Ding

Yan

2011

Chin. Sci. Bull.

View full text Add to dashboard Cite

Low-frequency noises in GaAs MESFET are usually observed when investigating the drain current and substrate leakage current under sidegate bias conditions. Experimental results show that the magnitude of low-frequency noises is in a direct dependency upon the sidegate bias and the noises in drain current will disappear if sidegate bias increases more negatively beyond a certain voltage. A mechanism associated with the substrate conductivity and the channel-substrate junction modulated by sidegate bias is proposed to explain the fluctuation of low-frequency noises.MESFET, low-frequency noise, substrate conductivity, channel-substrate junction Citation:Ding Y, Yan X L. Low-frequency noises in GaAs MESFET's currents associated with substrate conductivity and channel-substrate junction. Chinese Sci Bull, 2011Bull, , 56: 1267Bull, −1271Bull, , doi: 10.1007 MESFET is considered as one of the important devices for the applications of high power, high frequency and high efficiency microwave electric circuit [1,2]. However, as the demand for higher speeds and increased functionality in circuits, low-frequency noises (LFN) in currents, such as thermal noise, 1/f noise, generation-recombination noise, diffusion noise and shot noise, in various GaAs FET structures have been reported [3][4][5][6][7][8][9][10]. The main characteristics of these noises are: (1) LFN strongly depends upon the substrate materials. (2) The frequency of LFN is in the range of about 10 −2 to 10 2 Hz. (3) LFN is dependent on the fabrication procedure and bias condition. (4) LFN is sensitive to illumination. Recently LFN has received more attention due to its effect on the performance of low-noise microwave integrated circuits (MMICs).Although it is generally accepted that LFN results from the field-enhanced capture of electrons by deep traps, the exact mechanism is not fully understood. Miller and Bujatti attributed LFN directly to the oscillations in leakage currents in the semi-insulating (SI) GaAs substrate [5]. While Wager pointed out that LFN in channel current could not be simply attributed to the oscillations in leakage current of the substrate, but related to the peculiarities of channel-substrate junction [9].In this paper, LFN in MESFET's currents is investigated under sidegating conditions, and the mechanism is identified whereby the current fluctuation is directly related to the sidegate bias. Unlike Birbas's explanation in terms of an unreal negative capacitance of the depletion region in buffer-channel interface [11], we associate LFN with the substrate conductivity and channel-substrate junction modulated by sidegate bias. This study should be of value to elucidate the fundamental nature of noises modulation in GaAs ICs.

show abstract

GaAs MESFET interface considerations

Cited by 46 publications

References 17 publications

Low-temperature grown GaAs insulators for GaAs FET applications

Low-temperature grown GaAs insulators for GaAs FET applications

Effects of channel-substrate interface on hysteresis of sidegating effect in GaAs MESFETs

Low-frequency noises in GaAs MESFET’s currents associated with substrate conductivity and channel-substrate junction

Contact Info

Product

Resources

About