Effects of tunnelling current on millimetre-wave IMPATT devices

Abstract

In this paper, the influence of tunnelling on the RF performance of millimetre-wave (mm-wave) impact ionisation avalanche transit time (IMPATT) diodes operating in mixed tunnelling and avalanche transit time mode is studied by taking into account the parasitic series resistance of the device. The results show that the parasitic resistance of mm-wave IMPATTs increases and consequently the power delivered by the device decreases due to the consequence of band-to-band tunnelling. The critical background doping concentration and operating frequency are found to be 5.0 × 10 23 m −3 and 260 GHz, respectively, above which the influence of tunnelling on the RF performance of the device becomes predominant.

Noise Performance of Heterojunction DDR MITATT Devices Based on at W-Band

“…The authors have used a double-iterative simulation method [18,19,24,25,[28][29][30][31] to study the static and high-frequency properties of homojunction (N-Si ∼ -Si) and heterojunction ( -Si ∼ -Si 0.9 Ge 0.1 , N-Si ∼ -Si 0.7 Ge 0.3 , n-Si 0.9 Ge 0.1 ∼ -Si and n-Si 0.7 Ge 0.3 ∼ -Si) DDR IMPATTs operating at 94 GHz atmospheric window. Peak tunneling generation rate ( Tp ), peak avalanche generation rate ( Ap ), and ratio of Tp to Ap ( Tp / Ap (%)) of all the devices under consideration are listed in Table 2.…”

“…One-dimensional model of reverse biased Si ∼ Si 1− Ge DDR MITATT device shown in Figure 1 is considered for noise analysis. The DC electric field and current density profiles in the depletion layer of the device are obtained from simultaneous numerical solution of fundamental device equations, that is, Poisson's equation, combined carrier continuity equation in the steady state, current density equations, and mobile space charge equation subject to appropriate boundary conditions as discussed in detail in the earlier papers by the authors of [24][25][26]. A double-iterative simulation method described elsewhere [17] is used to solve these equations and to obtain the electric field and current density profiles.…”

“…These values are fed back as input parameters in the small-signal simulation program to obtain the admittance properties of the device such as avalanche resonance frequency ( ), optimum frequency ( ), negative conductance ( ( )), and corresponding susceptance ( ( )) as functions of frequency. Two secondorder differential equations are framed by resolving the diode impedance ( , ) into its real part ( , ) and imaginary part ( , ) [18,19,24,25,[28][29][30][31]. Here, ( , ) = ( , ) + ( , ), where ( , ) and ( , ) are, respectively, the negative specific resistance and specific reactance at the space point , for angular frequency of (frequency = 2 / ).…”

“…MITATT devices can provide higher efficiency, higher output power, and lower noise as compared to normal IMPATT diodes. The effect of tunneling on the high frequency properties of DDR Si IMPATTs operating at millimeter-wave and terahertz frequencies was studied and reported by Acharyya et al in their earlier paper [24,25] which showed that the critical background doping concentration and operating frequency above which tunneling effect becomes predominant are 5.0 × 10 23 m −3 and 260 GHz, respectively. The millimeterwave performance of IMPATTs operating in MITATT mode was studied by Acharyya et al from the shift of avalanche transit time (ATT) phase delay and reported in [26].…”