Diffusion of Iron into GaAs from a Spin‐on Source

Abstract

Iron was diffused from a spin-on glass film into n-type GaAs wafers at temperatures of 700~176The observed diffusion depths can be explained by a model with exhaustible diffusion sources. The diffusion coefficient of iron in GaAs has been estimated to be 1 x l0 s exp (-2.7/kT) in this temperature range. The resistivity of the diffused layer was in the order of 104 fl cm. The activation energy of the introduced levels was 0.53 eV for the diffusion at 700 ~ and 800~ which agrees well with the acceptor level of iron. The current-voltage characteristics of mesa diodes made of the diffused wafers showed no excess leakage current, which ensures that high-resistivity, p-type, iron-diffused regions can be used for junction isolation in GaAs integrated circuits.

Diffusion of vanadium in GaAs

“…The understanding of these processes provides information on the defects present in the crystal lattice. Although the diffusion of the 3d transition metal impurities in GaAs is faster compared to shallow impurities, there is a large difference in diffusion of these elements when compared to each other [1][2][3][4][5].…”

Charge storage characteristics of pnp GaAs layers prepared by iron diffusion

“…In both cases the current is on the order of 10 12 A when the bias voltage is less than 5 V, which demonstrates that a pn + p structure is realized as expected with low leakage current. The current density is on the order of 10 9 A cm 2 , and is less than the value in diodes fabricated by iron diffusion into HB-grown GaAs [2]. Because the currents in the range of 0.1 V to 3 V depend on the one-half or one-third power of the bias voltage, the generation current component is suspected to be dominant.…”

“…Iron diffusion was performed by an established procedure described elsewhere [2]. A brief description is as follows: the method uses solid diffusion of impurity from a spin-on glass (SOG).…”

“…After baking the film, the wafer is heat-treated at a prescribed temperature. The choice of the temperature allows overcompensation of n-type layers with donor concentration of up to 1 ´ 10 17 cm 3 [2]. In the present experiment, a temperature of 650 °C was chosen to introduce iron atoms at about 5 ´ 10 15 atoms cm 3 .…”

“…This means that iron doping into lightly doped n-type GaAs could render the crystal a weak p-type (p-type) by overcompensation of donors [2,3]. Furthermore, since the energy level is located off the middle at 0.71 eV of the energy gap, it invariably acts as an effective recombination center, but does not make an efficient generation center [4].…”