A substrate suitable for producing a high frequency electronic circuit. This substrate includes a support substrate having a controlled amount of interstitial oxygen and which is treated to precipitate at least some of the oxygen therein; and a useful layer supported by the support substrate. Advantageously, the support substrate has high resistivity and includes oxygen precipitates beneath the useful layer while also being free of depleted zones of oxygen precipitates adjacent the useful layer. This is prepared by the methods disclosed herein which are applicable in particular to SOI substrates.