5G and beyond
One of the challenges for chip makers is how to integrate III-V materials with silicon to make ultra-fast devices for 5G and other uses, which are compatible with conventional CMOS technology. In addition to silicon, III-V compound semiconductors are obtained by combining group III elements (essentially Al, Ga, In) with group V elements (essentially N, P , As, Sb). This gives us 12 possible combinations; the most important ones are probably GaAs, InP GaP and GaN.
IOT and 5G applications typically use sensors that transmit wireless data to anedge or cloud network. This requires a combination of RF capabilities with a small form factor and low operating power. A promising approach to achieve this combination is to create single chips that combine the capabilities of silicon CMOS with those of III-V devices, such as gallium nitride (GaN) and indium gallium arsenide (InGaAs). The unique properties of III-V compounds make then well suited for optoelectronics (LEDs) and communications (5G).
At IEDM, Intel talked described how low-leakage, high-k dielectric enhancement mode GaN NMOS and Si PMOS transistors were built monolithically on a 300mm Si substrate. The goal was to combine GaN’s high-frequency/-temperature/-power attributes with silicon CMOS circuitry’s digital signal processing, logic, memory and analog capabilities, to create compact devices for next-generation solutions for power delivery, RF and system-on-chip (SoC) applications. The researchers say both device types demonstrated excellent performance across a range of electrical specifications.
III-V materials offer higher electron mobilities than silicon, and HBTs made from them are very fast transistors often used for RF and other high-frequency applications. A key goal is to build them on 300mm silicon wafers instead of other substrates, to take advantage of silicon’s lower manufacturing costs. A team led by imec described how they used a unique nano-ridge engineering technique to build GaAs/InGaP HBTs on a 300mm silicon substrate.