High RF Performance AlGaN/GaN HEMTs on 6-in Si Substrate for Low Voltage Applications
Yuxi Zhou, Jiejie Zhu, Bowen Zhang, Qiyu Wang, Lingjie Qin, L. F. Wei, Mengdi Li, Binglu Chen, Mingchen Zhang, Yue Hao, Xiaohua Ma
Abstract
In this letter, AlGaN/GaN high electron mobility transistors (HEMTs) on a 6-inch Si substrate with excellent RF performance are presented for low voltage applications. Using regrown n+-InGaN ohmic contacts by metal-organic chemical vapor deposition, the ohmic contact resistance achieves an average value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.08~\Omega \cdot $ </tex-math></inline-formula>mm on the whole wafer. With a gate length of 220 nm and a source-drain spacing of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.2~\mu $ </tex-math></inline-formula>m, the device exhibits a saturation current of up to 1689 mA/mm and a peak transconductance of 436 mS/mm. Once the wafer was thinned to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\mu $ </tex-math></inline-formula>m, 3.6 GHz load-pull measurements for the HEMT with gate width (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}_{\text {g}}\text {)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 100~\mu $ </tex-math></inline-formula>m at low drain voltages (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {d}}\text {)}$ </tex-math></inline-formula> of 5-15 V indicate that the device exhibits maximum output power densities (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P}_{ {\text {out}, {max}}} )$ </tex-math></inline-formula> of 0.86-4.35 W/mm and peak power added efficiencies (PAE) of 63.96%-66.23%, which are the highest output power density and PAE from AlGaN/GaN HEMTs at the same operating voltage level in sub-6GHz. Furthermore, the HEMT with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}_{\text {g}}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times 125~\mu $ </tex-math></inline-formula>m also shows high PAE of 60.4%/61.19% and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P}_{ {\text {out}, {max}}}$ </tex-math></inline-formula> of 0.56/0.75 W/mm at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {d}} =5$ </tex-math></inline-formula>/6 V. The excellent properties of these AlGaN/GaN HEMTs on Si illustrate their suitability for addressing specific RF application scenarios, including portable communication devices, wireless sensor networks and so on.