Fabrication processes for high performance InAs-based HBTs

Abstract

The potential for InAs-based heterojunction bipolar transistors (HBTs) to be used for high speed, low power applications has been demonstrated.[l] The material properties that give InAs an advantage over InGaAs-based HBTs include a low bandgap, low electron effective mass, high peak velocity and high electron mobility. However, a new technology presents new challenges for process development engineers. In this talk, InAs-based HBT technology will be discussed. Several of the available fabrication processes will be presented as well as the device performance obtained from some of these options.The first major difference between InAs technology and other In-V HBT technologies is the

Shallow and Thermally Stable Ohmic Contacts to p-InAsP

“…InAs-based transistors are promising for applications requiring high-speed, low-power integrated circuits. 1,2 The use of strained alloys close in composition to InAs, such as Al x In 1−x As and InAs y P 1−y , adds further flexibility to the design of these devices. 3 Since the base layers of InAs-based heterojunction bipolar transistors are usually less than 50 nm, 3 shallow and thermally stable ohmic contacts are a critical factor for reliable high-speed devices.…”

“…The compositions of InAs y P 1−y of interest have y near 1, making past work on contacts to InAs of particular interest. Katz et al reported a specific contact resistance of 1 ϫ 10 −7 ⍀ cm 2 for Ti/Pt ͑50:60 nm͒ contacts annealed at 450°C for 30 s on p-InAs with a doping level of 1 ϫ 10 19 cm −3 , but mixing of Ti and InAs was observed by Auger electron spectroscopy ͑AES͒ in the samples annealed for 30 s at a temperature of 400°C. 4 Lysczek et al compared Pd/Pt/Au ͑3:50:145 nm͒ and Ti/Pt/Au ͑50:60:145 nm͒ contacts on the same p-InAs epi layer, and they found that the contacts with Pd as the first contact layer provided lower specific contact resistances than Ti-based contacts.…”

Proton Tolerance of InAs Based HEMT and DHBT Devices

“…The high mobility, high peak velocity, and low contact resistance and low bandgap of InAs, coupled with a large conduction band offset to AlSb, has allowed demonstration of high speed, low power HIEMT devices [1,2] and low Vbe, high speed DHBT devices [3,4]. Recent work has shown that circuits produced in these emerging device technologies exhibit high speed performance, as well as low DC power consumption [4][5][6][7][8], suggesting that these circuit technologies can play a critical role in the severely power-constrained environments of space-based systems.…”