Modeling of sheet carrier density and microwave frequency characteristics in Spacer based AlGaN/AlN/GaN HEMT devices

Self Cite

This paper reports a systematic theoretical study of Al0.23Ga0.77N/GaN/AlxGa1‐xN double‐heterojunction high electron mobility transistors (DH‐HEMTs) with a boron‐doped GaN cap layer under the gate. Boron containing GaN is a desired replacement for Schottky gate in DH‐HEMT to improve the resistivity and surface qualities of GaN cap with good structural properties, and the influence of polarization field in the GaN cap layer can be used to lift up the conduction band for normally OFF operation of the device. This study shows that the B‐doped GaN cap layer offers excellent device characteristics such as high threshold voltage VT of 1.92 V, steep subthreshold slope of ~ 72 mV/dec, high ON/OFF drain current ratio of ~ 107, extremely low subthreshold drain current Ids,LL ~ 10−9 A/mm, and low gate leakage current, Igs,LL less than 10−15 A/mm. For an Al0.07Ga0.93N back‐barrier/buffer, a high OFF‐state breakdown voltage (VBR,OFF) of 865 V is achieved at Ids = 1 mA/mm and Vgs = 0 V with substrate grounded and gate‐to‐drain distance and gate field plate length of 10 and 5 μm, respectively. The simulated high VT and VBR,OFF values are achieved due to the presence of increased back‐barrier height of the AlxGa1‐xN buffer and high Schottky barrier between the Boron‐doped GaN cap and gate metal. Finally, a DC to AC full‐bridge inverter circuit is designed to evaluate the benefit of B‐doped DH‐HEMTs based switching devices for an ultra‐low‐loss inverter circuit.

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Device characteristics of enhancement mode double heterostructure DH‐HEMT with boron‐doped GaN gate cap layer for full‐bridge inverter circuit

Mohanbabu¹,

Mohankumar²,

Raj

et al. 2017

Self Cite

“…where N i = (n s p s ) 0.5 . The various bound elements in the mobility model 24 are as follows: a = 2.61 × 10 −4 V s cm −2 , b = 2.9 × 10 −4 V s cm −2 , and c = 1.7 × 10 −2 V s cm −2 .…”

Section: Mobility Modelmentioning

confidence: 99%

Analytical modeling of 2DEG with 2DHG polarization charge density drain current and small‐signal model of quaternary AlInGaN HEMTs for microwave frequency applications

Anbuselvan¹,

Mohankumar²,

Mohanbabu³

2019

A physics-based analytical model for quaternary AlInGaN high electron mobility transistors (HEMTs) is developed including two-dimensional electron gas (2DEG) and two-dimensional hole gas (2DHG) for microwave applications. The DC and RF performance characteristics are explored by considering the quasi-triangular quantum well (QW). The derived charge carrier densities n s and p s are considered for energy subbands E o and E 1 inside QW. The 2DEG sheet carrier concentration density remains constant as long as 2DHG exists. From the derived model, the drain current (I d ), transconductance current gain (g m ), and cutoff frequency (f t ) for different gate length and width are verified with experimental data for upcoming nano-scale devices.KEYWORDS two-dimensional electron gas n s (2DEG), two-dimensional hole gas p s (2DHG), AlInGaN, drain current I d , quantum well (QW), transconductance current gain g m and cutoff frequency f t

“…Introduction of AlN binary layer in AlGaN/GaN and AlInN/GaN material system results in high polarization-induced sheet charge density at the heterointerface due to large polarization charges and conduction band offset. 10,12 The 2-dimensional electron gas (2DEG) mobility increases due to less alloy disorder scattering 13,14 and reduction of the electron-wave penetration into the AlGaN or AlInN barrier layer. 12 To achieve better performance, the aspect ratio of the device is the vital factor that influences the device operation.…”

Section: Introductionmentioning

confidence: 99%

“…10,12 The 2-dimensional electron gas (2DEG) mobility increases due to less alloy disorder scattering 13,14 and reduction of the electron-wave penetration into the AlGaN or AlInN barrier layer. 12 To achieve better performance, the aspect ratio of the device is the vital factor that influences the device operation. Therefore, the ratio between the gate length (L g ) and the gate-to-channel separation needs to be considered when L g decreases.…”

Section: Introductionmentioning

confidence: 99%

Modeling and simulation of DC and microwave characteristics of AlInN(AlGaN)/AlN/GaN MOSHEMTs with different gate lengths

Amarnath

Panda

Lenka

2018

In this paper, direct current (DC) and microwave characteristics are modeled and analyzed for AlInN(AlGaN)/AlN/GaN metal-oxide-semiconductor high electron mobility transistors with different gate lengths. The 2-dimensional electron gas sheet charge density (n s ) model is developed by considering polarization effect and flat-band voltage with lowest occupied energy level (E 0 ) in the quantum well.The drain current, transconductance, and gate charge model is developed by incorporating approximation of n s as proposed in this paper. Then, the cut-off frequency is calculated from the transconductance and gate capacitance model. The analytical model results are in good agreement with Technology Computer Aided Design simulation and experimental results from literatures for DC and microwave characteristics for the proposed gate lengths (0.1, 0.2, and 0.3 μm). From these characteristics, it is also observed that AlInN/AlN/GaN MOSHEMT shows superior DC and radio frequency performance as compared with AlGaN/ AlN/GaN MOSHEMT. AlInN/AlN/GaN MOSHEMT produces high drain current (2.34 A/mm) and high cut-off frequency (124 GHz) at smaller gate length.