Simultaneous Implant Activation and Isolation Formation in GaAs in a Single High-Temperature Anneal
- PDF / 333,856 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 43 Downloads / 156 Views
SIMULTANEOUS IMPLANT ACTIVATION AND ISOLATION FORMATION IN GaAs IN A SINGLE HIGH-TEMPERATURE ANNEAL KEI-YU KO, S. CHEN, G. BRAUNSTEIN, L.- R. ZHENG, and S.- T. LEE Corporate Research Laboratories, Eastman Kodak Company, Rochester, NY 14650-2011
ABSTRACT Using void-related compensation in Al-implanted GaAs, high-resistivity isolation regions that are thermally stable to high temperatures (> 700 1C) are demonstrated. The high-temperature thermal stability of the isolation regions allows the simplification of device processing in which a single hightemperature anneal (e.g., at 900 OC) can be used to activate the implant dopants in the device-active regions, and simultaneously to convert the Alimplanted regions highly resistive for electrical isolation. Other advantages of using void-related isolation will also be discussed.
INTRODUCTION Recently, we reported the formation of thermally stable implant isolation in n-type GaAs that exhibited sheet resistivity > 107 2/0I after Alimplantation and annealing at 900 °C [1]. The formation of voids in the implanted regions after high-temperature annealing was shown to be responsible for the development of high resistivity. These microscopic voids and the isolation regions are stable against subsequent high-temperature processing [2]. The method of forming thermally stable void-related isolation circumvents the limitation that other implant isolation techniques have. For instance, oxygen implantation has been widely used for creating isolation in GaAs [3-5]. However, the high-resistivity characteristic associated with damage-induced compensation is not stable with respect to high-temperature thermal treatment. Restoration to the initial resistivity occurs when the material is heat-treated at temperatures higher than about 650 IC [4,5]. However, processing at high temperatures is often required in GaAs device fabrication; for instance, thermal activation of Si-implanted GaAs is usually carried out at 850 to 900 °C [6,7]. Hence, damage-related isolation implant is often limited to the final stages of the fabrication processes. In this paper, we Mat. Res. Soc. Symp. Proc. Vol. 262. @1992 Materials Research Society
1086
report the result of a thermal stability study of void-related implant isolation. We show that the high-temperature thermal stability of void-related isolation can advantageously be used to simplify GaAs device fabrication. Namely, the thermal activation of implanted dopants and the formation of device isolation can be achieved simultaneously in a single high-temperature annealing step. We will also discuss other advantages of using void-related compensation for electrical isolation.
EXPERIMENT The samples were n' layers formed by implanting 60 keV, 3 x 1013 cm-2 of Si ions at room temperature into semi-insulating (SI) GaAs, followed by an activation anneal at 900 IC for 10 s. The condition was chosen to form a n' layer that is similar to the contact regions for GaAs metal-semiconductor field effect transistors. To achieve isolation, the n' layers were implante
Data Loading...
